NPPM Success and its measurements: A systematic literature review

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NPPM Success and its measurements: A systematic

literature review

Abstract:

New Product Portfolio Management is a dynamic decision process of evaluating, selecting, prioritizing, and allocating resources for choosing the right innovation projects within organizations. Managing the right innovation projects is of importance for long-run competitiveness. Prior research addressed the concept of NPPM success, however, a comprehensive understanding is still missing. Therefore, this study specifically looked at a detailed definition of NPPM success, to make the field of

NPPM success clearer for future research and NPPM practices. Also, a comprehensive set of measurements of NPPM success was given. This has been studied through a systematic literature review. Using the insights gained from this review, a path model has been generated. This path model

showed the importance of three main clusters: Portfolio information, portfolio-decision making, and portfolio methods/approach. Also, suggestions for future research came forward, suggesting that moderating effects will be influencing the relationships of the main clusters with NPPM success.

Author: Rianne Pluim

Student number: S3147223

MSc BA Strategic Innovation Management

Supervisor: Dr. K.R.E. Huizingh

Co-assessor: Dr. J.D. van der Bij

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1. Introduction

New products fail at an alarming rate. Approximately one in ten product concepts succeeds commercially, while only one in four development projects is a commercial success (Cooper, Edgett, Kleinschmidt, 2004). Thus, the right innovation projects have to be managed by firms to be successful, since this has far-reaching consequences for long-run competitiveness (Eggers 2012). Choosing the right innovation projects should be done through New Product Portfolio Management (NPPM), this is the dynamic decision process of evaluating, selecting, prioritizing, and allocating resources to product development projects (Cooper, Edgett, Kleinschmidt, 2001). Furthermore, portfolio management is a continuous process whereby new products and projects constantly get updated and revised, and in which new products are evaluated, selected, and prioritized whereas existing projects may be accelerated, killed, or deprioritized (Cooper, Edgett, Kleinschmidt, 1999). The New Product Portfolio Management has gained a central position in project management, development, research, and company management practice within firms (Martinsuo, 2013).

Cooper, Edgett, and Kleinschmidt (1999) argue that portfolio management and the prioritization of new product projects are vital for successful business performance. The question however arises: ‘What exactly is NPPM success?’. Cooper et al (1997) found three characteristics of NPPM success: strategic alignment, maximizing value, and balance. Thus, to gain NPPM success, managers have to understand that portfolio management is about making strategic choices. Strategic choices that management makes today determine what their business will look like five years out, it entails resource allocation and it deals with the critical issue of balancing resources available with the number of projects (Cooper, Edgett, Kleinschmidt, 1999). Nonetheless, a comprehensive understanding of NPPM success is still missing. A commonly accepted operationalization is however of importance since NPPM is a highly complex and uncertain process and studies clarifying antecedents are necessary (Meifort, 2015). The article of Cooper et al (1997) found three characteristics, but this study took place 23 years ago. Also, Martinsuo & Geraldi (2020) state that the dimensions of Cooper et al (1997) are only inward-oriented focused but NPPM success should also be focused on an outward-oriented focus. Thus, it remains unclear what NPPM success exactly is, and which definition is still relevant today. Therefore, the first part of this research will further explain the definition of NPPM success.

Besides the definition of NPPM success, this research will delve further into the concept of NPPM success by looking at how the concept is measured within articles. It is of importance to have a comprehensive set of measurements, so NPPM success will be measured consistently and differences within studies regarding the measurements will disappear. Also, which factors influence the success of NPPM will be researched. Through expanding the field of the NPPM success concept, it will become clearer what comprises NPPM success and what process will lead to a successful NPPM. Therefore, the research question of this study is: “What is NPPM success, and how can it be measured?”. Therefore, this research will contribute to the literature by searching for a comprehensive definition of NPPM success, its measurements, and factors influencing it, to get a clear understanding of the process of NPPM success. This can be of use for future research for having a consistent definition and measurements of NPPM success as well as to further understand the concept of NPPM success. This thesis is organized as follows: at first, the methodology will explain how this research has been conducted, and data has been found and analyzed. Then, the results will be discussed, where a definition of NPPM success will be given as well as an overview of the measurements of it, and last a path model with clusters influencing NPPM success. This will be followed by recommendations for future research, managerial implications, limitations, and a conclusion.

2. Methodology

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success were searched for in the literature. This section explains how this research was conducted, followed by the analysis and results.

To search for studies on NPPM success, the following databases were used: Business Source Premier and Google Scholar. At first, the keywords were determined. The following keywords were used by searching through the databases: New Product Portfolio Management, portfolio success, product portfolio performance, and product portfolio measures. To make sure that the articles found were sufficient for this study, some filters were selected. The document type was filtered into articles and chapters and the language selected was English. The keywords were used as a selection for the title, the subject, abstract, or keywords.

The search process went as follows. Every keyword would have been searched for individually in every database. This resulted in 1924 articles. To further reduce the number of articles, overlap between the keywords were removed from the database, and then, groupings were made. The articles were filtered into three groups. Since the main goal of this study is to find different insights of NPPM success within the articles, to come towards a broad and comprehensive view of the concept of NPPM success, a broad overview was needed. The first group of interest is meta-analyses and reviews. The second group was obtained by citation-based selection criteria and thus filtering on highly-cited papers. And the third group were recent papers (2017-2020) since those articles could be useful for our study but could not have been cited as much as older papers. Table 1 gives an overview of the selection process of the articles per group.

2.1 Group 1: Meta-analysis and reviews

Meta-analysis and review papers were found as followed. The above-stated keywords were searched for individually through both databases, and the words “review” and “meta” were added to the search process. This resulted in a total of 275 papers. Papers were at first judged by their title, resulting in that abstracts were only being read if the paper had one of the keywords, or a keyword partially in the title. This resulted in88 titles being good enough to read the abstract. Abstracts should be focused enough on NPPM. When NPPM (success) or portfolio performance/success was just mentioned but not really a part of the study, the paper would not have been downloaded. Eventually, only 9 meta-analysis or review papers were downloaded. Those meta-analysis or review papers were written in a proper analytical sense, with the remainder of being purely and/or narrowly focused articles, examples are articles focused on financial markets, architecture, accounting, law, or alliance portfolio. After downloading the papers, the full article was read and 3 articles were useful for this research. The 6 other papers turned out to be focused too much on New Product Development, or the information found turned out to be not relevant for the focus of this study, for example, reviews focused on context or industry differences.

2.2 Group 2: Highly cited papers and top and very good journals

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Since citations are not visible in the database of Business Source Premier, the quality was assessed by looking at papers published in top and very good journals. Articles were searched for by selecting journals that are in the SOM list of top and very good journals (Rug, n.d.). This resulted in 106 articles published in top and very good journals. 3 of those articles were already integrated into group 1, whereas 3 other articles were already found through the highly-cited method. Thus, those 6 articles were already judged on their value for this study and therefore not further integrated into this selection process. 49 other articles had titles that met the requirements stated before, and thus those abstracts were being read. 23 of those abstracts did not have enough overlap with the subjects of this study and thus 26 papers were being downloaded and fully read whereas information of 4 papers were eventually being integrated into this study.

The papers that were downloaded were published in the following journals stated on the SOM list: Journal of Product Innovation Management, Industrial Marketing Management, Management Science, the Academy of Management Journal, Research Policy, Journal of Business Research, Journal of Operations Management and European Journal of Operational Research. Excluded from the literature search were: book-reviews, non-business, and papers in which the term ‘portfolio’ was used to address a nonrelevant subject for this research, such as ‘accountancy’, ‘financial outcomes’, or ‘alliance portfolio’. Also, articles that were too much focused on the single project instead of the portfolio were not being read since they were not useful for this study.

2.3 Group 3: Recent papers

Since recent papers could have been discriminated against during the citation-based method, because of the short amount of time they could have been cited. The initial pool of search results was filtered for recent papers (2017-2020). This resulted in a total of 1372 search results for all search terms together. 9 results had overlap with other search terms or were already found in the two groups mentioned before and therefore not further mentioned in this search process. Only 149 titles had at least one of the search terms mentioned (partially) integrated and thus met the requirements. After reading the abstracts, 54 abstracts seemed good enough for this study and thus those articles were being downloaded. 12 of those papers were eventually being used for this study.

2.4 Reference papers

Some articles were also found through references stated in the articles that were found during the search and reading process. When the reference mentioned in the text did seem to have overlap with the subject of this study, the paper would have been downloaded and fully scanned. This resulted in19 reference papers that were useful for this study.

Table 1. Overview of article selection

Titles read Duplicates Abstracts read Articles downloaded Articles used

Review articles (Group 1) 275 0 88 9 3

Highly-cited articles (Group 2)

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Published in top and very good journals (Group 2)

106 6 49 26 4

Recent articles (Group 3) 1372 9 149 54 12

Reference papers / / / / 19

Total 1924 22 372 137 54

3. Analysis and synthesis

This section provides an analysis of the findings of the systematic literature. The aim of the analysis is to break down individual studies into constituent parts and describe the relations among the papers (Denyer & Tranfield, 2009). The articles obtained by means of the above-stated search process are analyzed based on the criteria listed in Table 2. These characteristics are needed to synthesize, integrate and extract information and the results of different studies on the research topic. This table is used and filled in for each article.

Table 2. Characteristics of articles

Title Title of the article

Year Year of publication of the study

Research location Country the research took place

Research method Type of study

Operationalization The definitions of NPPM success

Measurements How is NPPM success measured within the study

Factors influencing NPPM Success Which factors influence NPPM success and in what way

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4. Results

4.1 Definitions NPPM success

As already mentioned before, Cooper et al (1997) state that NPPM success exists out of three elements: 1. Strategic alignment, 2. Maximize value, 3. Balance. However, this is not an exact definition of what NPPM success implies. Therefore, definitions of NPPM success were searched for in the articles found during the search process. One noteworthy aspect that stood out during the analysis of the articles was that a lot of articles referred to the three dimensions of Cooper et al (1997). Cooper et al (2001) further expanded their definition by adding the importance of having the right number of projects and having good time to market to avoid gridlock, stating that positive portfolio results are having a balanced, strategically aligned, high value portfolio, with the right number of projects, and good times-to-market (Cooper et al, 2001). Another extension of the definition of Cooper et al (1997) was made by Kock, Heising and Gemünden (2015) by adding the importance of preparing innovation portfolios for the future. Jonas, Gemünden and Kock (2012) however divided the second dimension of maximizing value into two dimensions namely: 1. The average project success over all the projects in the portfolio in fulfilling time, budget, quality and customer satisfaction objectives. 2. The exploitation of synergies between projects.

Jonas et al (2012) thus showed the importance of the average project success, on top of that, other articles also focused on individual project success as being important for NPPM success. Stating that the success of project portfolio management is dependent upon the success of a project and that the collection of the projects must be successful for the portfolio to be successful (Olson, 2017). This corresponds with the definition of Patanakul (2015) that the success of the portfolio should be linked to the success of the projects, based on the project value or benefits. And to manage this correctly, the management should be done in such a way that the performance becomes predictable for the PPM, so that anticipating on this performance in advance becomes possible (Patanakul, 2015).

One of the articles that mentions different definitions of NPPM success is the article of Brasil and Eggers (2019). They refer to a combination of the definitions of Ernst (2002) and Klingebiel & Adner (2015). According to them NPPM success is a dynamic capability that fundamentally affects the ability to add, subtract and reposition products, linking to innovative performance at both granular and organizational levels (Ernst, 2002) (Klingebiel & Adner, 2015). Another definition mentioned by Brasil and Eggers (2019) is that successful portfolio management is a managerial mechanism where companies balance their efforts in exploiting their established viable resource to explore new sources of value creation. The balance must be made regarding decision-making and has direct effect on the firm’s ability to pursue radical and incremental innovations concomitantly (Chandrasekaran, Linderman, & Schroeder, 2015; Chao & Kavadias, 2008). These definitions thus state that for NPPM to be successful, organizations should have a constant mechanism for making decisions, mainly focused on the resources and the balance within, which affect the innovative performance of portfolios. These definitions overlap with the definition of Turner & Müller (2003) who state that portfolio decisions must balance a multitude of conflicting goals of an organization and that these decisions cannot be taken in a vacuum but must be balanced against other organizational performance measures or pressures.

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being made should be focused on the goal of the organization. Thus, the balance dimension as well as the alignment of the organization is being mentioned, the maximizing value part is not explicitly stated, however, the importance of creating value is.

Another point of view regarding the definition of NPPM success is by looking at an inward oriented focus and an outward oriented focus. The dimensions of Cooper et al (1997) focus on the inward oriented focus, however, according to Martinsuo and Geraldi (2020), the outward-oriented focus should also be considered during the management of portfolios. The reason is that project portfolio success draws on what the firm, its shareholders and its customers value and therefore, conditions should be created where the value for the multiple stakeholders will be generated so impact in the context will be achieved (Martinsuo & Geraldi, 2020).

Thus, when looking at the definitions regarding NPPM success, multiple things come forward. Firstly, it can be concluded that even though the dimensions of Cooper et al (1997) were stated over more than 20 years ago, they are still important for the NPPM literature this day. By combining all the expansions made regarding the definition of Cooper et al (1997), we can conclude that it will result in the following definition of NPPM success: NPPM success exists out of the following dimensions: 1. Strategic alignment. 2. Maximizing value, which is further divided into 2a. average project success and 2b. synergies. 3. Balance 4. Have the right numbers of projects 5. Have good time to market and 6. prepare for the future.

Some noticing points come forward when looking at the definitions that do not refer to the dimensions of Cooper et al (1997). The first one is that both the definitions mentioned in the study of Brasil and Eggers (2019) and Turner and Müller (2003) are more detailed definitions then the definitions of Cooper et al (1997). However, they still have overlap with the dimensions of Cooper, since they both refer to creating value, having balance and focusing on the strategic goals of the organization. Also, the decisions being made should not only be focused inward-oriented, but organizations should also have an outward-oriented focus for managing their portfolio successfully, to focus on the value created for stakeholders (Martinsuo & Geraldi, 2020).

When combining the definitions based on Cooper et al (1997) and the other definitions, it shows that the definitions of Cooper et al are explicitly focused on multiple dimensions, stating how portfolios are going to be successful. The articles mentioned in Brasil and Eggers (2019) and Turner and Müller (2003) state the importance of the decision-making. Thus, it can be concluded that decision-making is important regarding the dimensions of Cooper et al (1997), and the added expansions of Cooper et al (2001), Kock et al (2015), and Jonas et al (2012). However, there should also be more focus on an outward oriented look, to create value for the stakeholder which thus should be added to the definition based on the dimensions of Cooper et al (1997,2001), Kock et al (2015), and Jonas et al (2012). Concluding that the definition of NPPM success should be as followed: NPPM success exists out of the following dimensions: 1. Strategic alignment. 2. Maximizing value, which is further divided into 2a. average project success and 2b. synergies. 3. Balance 4. Have the right numbers of projects 5. Have good time to market and 6. prepare for the future, whereas also an outward-oriented focus should be implemented, focused on the different stakeholders (Cooper et al, 1997;2001, Kock et al (2015), Jonas et al (2012), Martinsuo & Geraldi, 2020).

4.2 Measurements of NPPM success

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Since the measurements are mostly dependent on how NPPM success is defined within an article, it also comes forward that besides the extensions made regarding the definition of NPPM success of Cooper et al (1997), the measurements are also being extended. As already mentioned, maximizing value has been divided into two dimensions. The first one, average single project success is measured through the following factors: budget, schedule, quality, adherence, and customer satisfaction of all projects in the portfolio (Teller, Kock, 2013). Synergies are measured through a multi-item scale of three items: 1. During the project execution, development synergies between projects are rigorously exploited. 2. After project completion, exploitation synergies between projects are rigorously exploited. 3. We hardly ever have double work or redundant development (Kopmann, Kock, Killen, Gemünden, 2017). Also, future preparedness was added to the definition of Cooper et al (1997), which can be measured through the following three items of a multi-item scale: 1. We sufficiently develop new technologies and/or competencies in our projects. 2. With our projects, we are a step ahead of our competition with new products, technologies, or services. 3. The projects enable us to shape the future of our industry (Kopmann et al, 2017). The number of projects and the time to market are the last two dimensions that should be measured for NPPM success (Cooper et al, 1999). The number of projects is measured through a natural logarithm of the number of projects that comprise the portfolio (Kopmann et al, 2017). And the last dimension, the time to market looks at if projects are done on time (Cooper et al, 1999), however, an explicit measurement of this factor was not found.

Table 3 summarizes all measurements of NPPM success found in the literature. When looking at this table it is visible that there are multiple differences between the measurements. However, when looking at these measurements critically, it is clear that there is a lot of overlap between the measurements. A difference that comes forward is that there are multiple amounts of dimensions being measured. Varying from two dimensions used by Panicker & Tiwari (n.d.), as well as Beringer et al (2013), whereas Cooper et al (1999), Teller & Kock (2013), Oosthuizen et al (2017) and Voss & Kock (2013) use six dimensions that need to be measured. This corresponds with the level of detail within the articles, the article of Cooper et al (1997) focuses on three broad dimensions, however, these dimensions are specified further into the articles where more dimensions are being used. The dimension of maximizing value is divided into two dimensions and also other dimensions, thus making the measurements more detailed. Also, other insights are considered, both the articles of Tawari & Panicker (n.d.) and Beringer et al (2013) take a broader look by making a difference between long term and short-term aspects. The short term perspective refers to the cumulative success of the projects in a portfolio, and the long term perspectives refers to the strategic fit of the portfolio. The cumulative success of the projects as well as the strategic fit are both already mentioned in the definitions of Cooper et al (1997;2001), also, more dimensions are added to the article of Cooper et al (1997;2001), resulting in that these dimensions will be used for this study.

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Thus, it can be concluded that there is a widely accepted base of the measurements of NPPM success in this literature. Overall, the articles based their measurements on the three dimensions of Cooper et al (1997), however, measurements were being added based on the extended definition mentioned before. And therefore, the following dimensions seem to be of importance for measuring NPPM success: 1. Value maximization. 1a. Average single project success. 1b. Synergies. 2. Balance. 3. Strategic fit. 4. Having the right number of projects. 5. Right time to market (no gridlock) 6. Future preparedness. How these dimensions could be measured is explicitly stated in the first and second paragraph of section 4.2.

Table 3. Overview of NPPM measurements in the articles

Author(s) Year Measurements NPPM success

Cooper, R.G., Edgett, S.J., Kleinschmidt, E.J.

1997 Managers use three broad dimensions to evaluate the firm’s portfolio of new product projects:

1. Value maximization, measured through financial returns such as long-term profitability or return on investment.

2. Balance, evaluate projects based on the extent to which they ensure that the mix of NPD projects is proportional across multiple concerns (project completion date, technical risk, return on investment, etc). 3. Strategic fit, assess projects in terms of the extent to which they reflect the firm’s strategy.

Cooper, R.G., Edgett,

S.J., Kleinschmidt, E.J.

1999 Portfolio performance was measured on six metrics:

1. Having the right number of projects in the portfolio for the resources available.

2. Voiding pipeline gridlock in the portfolio—undertaking projects on time and in a time-efficient manner.

3. Having a portfolio of high-value projects

4. Profitable, high- return projects with solid commercial prospects, 5. Having a balanced portfolio (long vs short, high vs low risk) 6. Having a portfolio of projects that are aligned with the business’s strategy

Yang, Y., Xu, D, L. 2016 1. Strategic fit

2. Average project success 3. Synergy

Tiwari, P., Panicker, S.

(Not shown)

1. Long term strategic context of portfolio strategic fit (The amount of the intentions and needs related to portfolio’s projects are aligned with the entire organization).

2. Short term operational context of average project success (The three restrictions to deliver project as per specifications within budget and on time)

Kopmann, J. 2013 Project portfolio success comprising four sub-constructs. 1. Average project success

2. Future preparedness 3. Strategy integration 4. Synergy exploitation Kopmann, J., Kock, A., Killen, C. P., Gemünden, H. G. 2014

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1. Strategy implementation (successful project portfolio management) 2. Future preparedness (the organizations preparedness for the future in terms of technological assets and competences)

3. Portfolio balance (the equilibrium of risks, long- and short-term opportunities and the steady utilization of resources within the project portfolio‟s execution)

4. Average project outcome (the respective indicators for average project success should not refer to the adherence to cost, time and scope but rather to quality of the project’s outcome and the satisfaction of the project customer)

5. Synergy exploitation (the added value that emerges from dedicated portfolio management in addition to the single projects‟ contribution through the capitalization of interdependencies and the avoidance of redundancies)

Teller, J., Kock, A. 2013

Project portfolio success comprising six sub-constructs:

1. Average project success (Budget, schedule, quality adherence, customer satisfaction of all projects in the portfolio)

2. Average product success (commercial effects such as goal-achievement regarding market success, Return-on-Investment, break-even, or profit of all projects in the portfolio)

3. Strategic fit (the extent to which all projects reflect the corporate business strategy)

4. Portfolio balance (the balance of the project portfolio concerning risks and expected benefits)

5. Preparing for the future (deals with the long-term aspects and considers the ability to seize opportunities that arise after the projects have been brought to an end)

6. Economic success (the short-term economic effects at the corporate level, including overall market success and commercial success of the organization or business unit)

Kock, A., Heising, W., Gemünden, H,G.

2015

A second-order construct that consists of five dimensions:

1. Business success (the impact of the portfolio on the firm’s business performance)

2. Average economic success of products and project results (The impact of the portfolio on the individual product level)

3. Strategic fit (the degree to which all projects combined are consistent with and reflect the organization’ s business strategy)

4. Portfolio balance (the strategic perspective of balancing existing and new technologies and application areas—in addition to risk—within the project portfolio)

5. Preparing for the future (the benefits and long-term opportunities for the organization that are rooted in the project portfolio and even before that in the ideation phase)

Ghasemi, F., Sari, M,H,M., Yousefi, V., Falsafi, R.,

Tamošaitiene, J.

2018

The main portfolio management objectives are: (1) Portfolio value maximization;

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(3) Portfolio balance; and (4) Right number of projects

Oosthuizen, C., Grobbelaar, S.S., Bam, W.G.,

2017

Maximizing value can be divided into two separate dimensions: 1. Average single project success (time, quality, budget, and customer satisfaction. And 2. The use of synergies between projects.

The top six success criteria found in the literature are the following in ranking order:

1. Projects linked to strategy 2. Portfolio balance.

3. Average single project success. 4. Use of synergies.

5. Future preparedness. 6. Maximizing value.

But how the success should be measured depends on the choice, project, and interpretation of the researcher or practitioner.

Beringer, C., Jonas,

D., Kock, A.

2013

1. Operative short-term perspective: The cumulative success of all projects in a portfolio.

Therefore, average project success is defined along the three familiar dimensions of the project management triangle: cost, schedule and quality.

2. Strategic long-term perspective Strategic fit of a portfolio,

In the context of project portfolio management, we define strategic fit as the degree to which the objectives and demands of a portfolio's projects are consistent with the objectives and demands of the overall organizational strategy

Meskendahl, S. 2010

Divided value maximization into two separate dimensions: (1) the average single project success of the portfolio regarding the fulfilment of time, budget, quality, and customer satisfaction objectives (2) the use of synergies between projects within the portfolio, which covers the interdependences between projects.

(3) The portfolio's overall fit with the firm's business strategy and (4) the portfolio's balance are the third and fourth dimensions on project portfolio success as suggested by Cooper et al (2002).

Voss, M., Kock, A. 2013

Defined project portfolio success as a multi-dimensional second-order construct with six sub-constructs:

1. Overall business success

2. Economic success of products and project results 3. Strategic fit

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Jonas, D. 2010

The success of a project portfolio management system is multidimensional consisting of the three dimensions of

(1) Process effectiveness (Information quality, allocation quality, cooperation quality)

(2) Portfolio success (Average project success, use of synergies, strategic fit, portfolio balance)

(3) Portfolio-related corporate success, (business success, preparing for the future) which will be affected by changes in the PPM system consecutively.

Kraiczy, N.D., Hack, H., Kellermans, F.W.

2014

New product portfolio performance:

- Patent counts or citations (Hagedoorn & Cloodt, 2003)

- Degrees of product innovativeness (Miller & Friesen, 1982; Prajogo & Ahmed, 2006).

Most approaches measure new product performance on the project level and use multiple items that combine product characteristics, financial market performance, and development efficacy (Griffin & Page, 1996; Salomo,Weise, & Gemünden, 2007). To measure new product portfolio performance, this study follows the holistic approach of Cooper and Kleinschmidt (1995), who measure, on a variety of dimensions, the impact of the totality of new products on the market.

Kester, L., Griffin, A., Hultink, E. J., Lauche, K.

2011 Cooper et al (2001) portfolio performance measures: 1. Strategic Alignment 2. Maximizing portfolio value 3. Balance

4.3 Factors influencing NPPM success

Besides the fact that there are multiple measurements for NPPM success, there are also multiple factors found in the literature that influence NPPM success. The factors found were at first critically evaluated before they were being used for this research. The scope of the research is focused on the practices regarding portfolio management and NPPM success. Factors that did influence NPPM success but were not focused enough on portfolios, and thus referred for example to the management of a single project or the overall management of the company, were not included. When the list of factors was complete, the factors were grouped into clusters. Resulting in the clustering of the factors mentioned in table 4. Clusters were made if the factors were similar in subject and therefore took place around the same moment in time during the portfolio process.

4.3.1 Cluster 1: Portfolio Information

The first cluster is the cluster Portfolio Information. This cluster consists of variables that focus on the information needed regarding the successful management of New Product Portfolio. It comprises the information of projects, the information flow from project level to portfolio level, and information regarding risks within the portfolio. Thus, the portfolio information is the information of the project on the portfolio level as well as the information regarding the portfolio itself.

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factor has been tested as a significant positive factor for NPPM success (Müller, Martinsuo, Blomquist, 2008). Therefore, it can be concluded that the information of the projects is important for managing the portfolio, as well as channeling the information from the project level to the portfolio level.

Also, the information regarding risks is incorporated into this cluster. The Project Portfolio Risk Management quality exists out of the following factors: risk coping capacity, risk transparency, and risk management efficiency (Teller, 2013; Teller, Kock, 2013). Risk coping capacity is defined as recognizing and countering occurring risks (Teller, Kock, 2013) and is tested positive for its relationship with NPPM success. Risk transparency is also being tested positively significant towards portfolio success and it refers to identifying major risks, recognize the risk sources, and detect cross-portfolio risks due to interdependencies within the portfolio (Teller, Kock, 2013). However, the risk management efficiency has not been tested yet, it implies cost efficiency of the input-output relation of the risk management process (Teller, 2013). The last factor is risk prevention, this factor has a significant positive effect on risk coping capacity however, it also shows a significant positive direct impact on NPPM success (Teller, Kock, 2013). Thus, the factors regarding risk are also important for NPPM success, since all factors except risk management efficiency are tested positively and significant towards their relation with NPPM success. Therefore, it can be concluded that it is important to be informed regarding the risks within the portfolio to make the management of New Product Portfolio successful. All of the factors mentioned are stated to have a direct positive effect on NPPM success, some of the factors are not tested quantitatively however the relation with NPPM success is mentioned in previous literature. Therefore, a direct linkage between the cluster Portfolio Information and the cluster of NPPM success is stated in this research. However, this research also suggests that portfolio information influences the decision making of the Portfolio. The reason for this is that for making decisions, information is needed. Thus, this study expects that the quality of the information and the successful implementation of the information cluster affects the decision making and its results.

Table 4.1 Cluster variables and the factors within: Portfolio information

Numbers behind the factors within a cluster refer to the article they are mentioned in, the numbers correspond with the reference list. Article numbers with * refer to another article where the corresponding factor is derived from.

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4. Risk coping capacity (52) 5. Risk transparency (52) 6. Risk prevention (52) 7. Portfolio reporting (41) Risk management efficiency: + 4. + 5. + 6. + 7. + p < 0.05 Risk management efficiency: Not tested 4. Tested: b = 0.3, p < 0.01 5. Tested: b = 0.34, p < 0.01 6. Tested: b = 0.3, p < 0.01 7. Tested, b = 0.123 p < 0.01 4. / 5. / 6. / 7. / 4. / 5. / 6. / 7. / - Qualitative proposition 4. Empirical investigation - quantitative cross-industry 176 firms 5. Empirical investigation - quantitative cross-industry 176 firms 6. Empirical investigation - quantitative cross-industry 176 firms 7. Quantitative 242 responses to questionnaire

4.3.2 Cluster 2: Portfolio Decision Making

The second cluster is the cluster Portfolio Decision Making. This research suggests that the cluster Portfolio Decision Making mediates the relationship between Portfolio Information and NPPM success. Suggesting that information will be of more worth to the success of NPPM when good decisions are being made. However, Portfolio Decision Making itself also has a positive direct relationship with NPPM success. The cluster Portfolio Decision Making refers to the decisions being made regarding the projects within the portfolio and the management of the portfolio itself.

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importance that the decisions being made are of good quality. Another factor that is part of the portfolio decision-making cluster is the factor portfolio management activities, this has not been tested in the article of Yang et al (2016), but it comprises all activities regarding the management of the portfolio. The last factor of this cluster is Project Portfolio Management quality (PPM quality), which has been tested significantly positive to NPPM success (Jonas, 2010; Teller et al, 2012). Thus, it is suggested that the management activities are of importance since the quality of the management has been tested significantly positive to NPPM success.

The last two factors are agility and focus. Agility refers to a firm being agile in how they make and implement NPD decisions (Kester, Hultink, Griffin, 2014) and is related to all three dimensions of Cooper et al (1997), balance, strategic fit, and maximizing value. When the firm is agile, resources can be shifted quickly and projects can be eliminated quickly (Kester et al, 2014). Thus, agility refers to the quick actions being taken and to the flexibility regarding decisions of the portfolio. Focus is tested positively on strategic alignment and maximizing value (Kester et al, 2014). There is focus when a firm focuses on development efforts on those projects that achieve long-term goals (Kester et al, 2014). Thus, the cluster portfolio decision-making refers to all factors that are related to the decision-making process within portfolios and all have a positive direct effect on NPPM success.

Table 4.2 Cluster variables and the factors within: Portfolio decision-making

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evaluate process (58*) 5. Decision quality (24*) 6. Focus (25) 7. Agility (25) 8. Project portfolio structuring (39) 9. Portfolio management activities (58) 10. PPM quality (21, 50) 5. + 6. + 7. + 8. + 9. +/- 10. + 5. Not tested 6. Tested, α = 0.80 7. Tested, α = 0.74 8. Proposition Not tested 9. Not tested 10. Tested: b = 0.64, p < 0.01 5. / 6. / 7. / 8. / 9. / 10. / 5. / 6. / 7. / 8. / 9. / 10. / 169 managers 5. Qualitative 6. Quantitative, cross-industry, 378 informants from189 firms 7. Quantitative, cross-industry, 378 informants from189 firms 8. Qualitative study 9. Scenario analysis on Bayesian Networks Case study. Questionnaire 169 managers 10. Quantitative, cross-industry, 79 firms

4.3.3 Cluster 3: Portfolio Methods/ Approach

The last main cluster is the cluster Portfolio Methods/ Approach. This cluster exists out of only three factors, which are: Portfolio Method, CCPM concepts and tools and, traditional practices of PPM. The cluster refers to which method and tools are being used within NPPM and how this influences the success of NPPM.

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which result in lower performance regarding portfolio management (Cooper et al, 1999). The factor Critical Chain Project Management Concepts and Tools describe the management process whereby the interaction between projects and time management are considered. An example of a CCPM tool is protection buffers. Protection buffers protect project completion from uncertainties by having a buffer at the end of the project completion path (Luiz et al, 2019). When comparing traditional practices of portfolio management to Critical Chain Project Management Concepts and tools, it turns out that both result in a positive effect on NPPM, however CCPM concepts and tools has a stronger positive relationship with portfolio success than traditional methods (Luiz et al, 2019). Thus, the methods as well as the tools used during portfolio management influence the NPPM success directly.

Table 4.3 Cluster variables and the factors within: Portfolio methods/approach

Cluster variable Factors within-cluster variable Positive /negative relationship with NPPM Success Significance and correlation with NPPM success Relationship with indirect variable Significance / correlation with indirect variable Type of research Portfolio Methods / Approach 1. Portfolio method (10) 2. CCPM concepts & tools (33) 3. Traditional practices PPM (33) 1. +/- 2. + 3. + 1. Concluded from survey data 2. Stronger than traditional methods ρ = 0.637, p < 0.01 3. Less effective than CPPM concepts & tools, ρ = 0.511 p < 0.05 1. / 2. / 3. / 1. / 2. / 3. / 1. Detailed survey questionnaire, 205 firms 2. Quantitative, correlation analysis, non-parametric tests, questionnaire 79 firms 3. Quantitative, correlation analysis, non-parametric tests, questionnaire 79 firms

4.3.4 Moderating cluster: Portfolio stakeholders

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The direct effect of Portfolio Stakeholders on NPPM success is already mentioned in other literature, stating that stakeholder behavior and stakeholder management are key success factors for portfolio success (Beringer, Jonas, Gemünden, 2012). The top managers’ involvement has been tested in the study of Yang et al (2016) and contributed to the portfolio success for 8.2%, and lastly the factor stakeholder of the portfolio as a whole. This factor refers to the stakeholders who are directly involved into the PPM process and can influence the success of the portfolio or are affected by it (Beringer et al, 2012). The factor has not been tested quantitatively but it is expected that this will positively influence the NPPM success directly (Beringer et al, 2012).

The moderating effect of portfolio stakeholders on the relationship between portfolio decision making and NPPM success has not been tested or mentioned in the literature yet. However, this study suggests the moderating effect since it expects that stakeholders will influence the way decisions are being made and when they are being perceived as successful for the portfolio. For instance, top managers take a look at the company as a whole and look at strategic issues, therefore they can have different requirements for the portfolio than lower-level managers. The same applies to the stakeholder of the whole portfolio, the stakeholder of the portfolio as a whole takes a look towards the complete portfolio, whereas a stakeholder or manager of a single project only looks at the individual project. Therefore, suggesting that the stakeholder of a single project wants the single project to do as best as possible whereas the stakeholder of the portfolio as a whole can see that changes have to be made in order for the portfolio to be as successful as possible. Thus, it is assumed that the stakeholder of the portfolio as a whole influence the effect of decision making on NPPM success, since the stakeholder can have different requirements than for example a single project stakeholder and can therefore change the effect the decision-making has on the success of NPPM. However, the moderating effect has not been tested yet and therefore is a suggestion for future research.

Table 4.4 Cluster variables and the factors within: Moderating cluster: Portfolio stakeholders

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4. Top managers involvement (58) 4. + 4. Tested, contribute for 8.2% to success 4. / 4. / 197 firms 4. Scenario analysis on Bayesian Networks Case study. Questionnaire 169 managers

4.3.5 Moderating cluster: Early phase management

The cluster early phase management refers to processes that affect NPPM success but are taken place early in the process. The factors within the early phase management do not have a direct effect on NPPM success itself, however, they do influence factors within the clusters that do have a direct effect on NPPM success. The first factor that is part of this cluster is the project portfolio formalization, which has a positive effect on the factor of PPM quality, and project portfolio complexity positively moderates this relationship (Teller et al, 2012). The variable PPM quality itself is already mentioned as a part of the portfolio decision-making cluster.

Besides the fact that the variables influence a single factor within the Portfolio decision-making cluster, the early phase management is also expected to have a moderating effect on the relationship between portfolio decision making and NPPM success. This moderating effect is expected because of the high probability that management early in the portfolio management process will influence the way decisions are being made and also how the decisions will have an impact on the NPPM itself and thus its success. Therefore, it is expected that good early phase management will positively contribute to the relationship between portfolio decision making and NPPM success.

Also, the integration of PPRM is part of the early phase management cluster, this variable has a positive effect on PPRM quality (William & Rūta, 2017), which is part of the Portfolio Information cluster and has a positive effect on NPPM success. The cluster early phase management is expected to have a moderating effect on the relationship between portfolio information on portfolio decision making and portfolio information on NPPM success. This moderating effect is expected for the fact that the early phase management will affect how there will be dealt with information within the organization. The portfolio information will be dealt with differently through the early phase management, expecting that good early phase management will positively influence the relation between portfolio information and NPPM success. This relation is expected since for example, the formalization will result in better information processing for NPPM success. Thus, the relationship between portfolio information and NPPM success will be stronger when the early phase management is integrated properly. Also, it is expected that the relationship between portfolio information and the portfolio decision-making will be positively moderated through the early phase management. Expecting that the early phase management will influence how there will be dealt with information and by managing the information even better the decision-making will become more successful. Thus, it is expected that early phase management moderates the relationship of portfolio information on decision making and NPPM success, as well as the relationship of portfolio decision making on NPPM success. However, these moderating effects have not been tested yet.

Table 4.5 Cluster variables and the factors within: Moderating cluster: Early phase management

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Cluster variable Factors within-cluster variable Positive /negative relationship with NPPM Success Significance and correlation with NPPM success Relationship with indirect variable Significance / correlation with indirect variable Type of research Moderating: Early Phase Portfolio Management 1. Portfolio management formalization (50) 2. Project portfolio complexity (50) 3. Integration PPRM (57) 1. / 2. / 3. / 1. / 2. / 3. / 1. + → PPM quality 2. + → Moderates the effect of project portfolio management formalization on PPM quality 3. + → PPRM quality 1. Tested, b = 0.20 p < 0.01 2. Tested, - project interdependency b = 0.10 p < 0.05 - portfolio size b = 0.06 p < 0.05 3. Not tested 1. Quantitative, cross-industry, 134 firms 2. Quantitative, cross-industry, 134 firms 3. Literature review

4.3.6 Moderating cluster: Organization Mindset

The third moderating cluster is the Organization Mindset. This cluster comprehends the culture and mindset of the organization and how they deal with their portfolio management. The factor portfolio mindset is tested positive towards its relation with NPPM success (Kester et al, 2014). It is defined as when the firm has a complete overview of the entire portfolio, as well as in-depth knowledge about each NPD project (Kester et al, 2014). Knowledge sharing is also positively related to NPPM success (Jiao, Saeed, Fu & Wang, 2019). The other three factors have not been tested. The analytic cognitive style is the consistent manner in which individuals approach perceptual and intellectual activities such as problem-solving (Van Bruggen, Lilien, Kacker, 2002). According to McNally, Durmusoglu, Calantone, and Harmancioglu (2009), it is expected that the higher the analytic cognitive style is, the more detailed evaluation of criteria will be integrated into the balance dimension. Thus, the factor analytic cognitive style has a positive direct effect on the NPPM success dimension balance (McNally et al, 2009). The ambiguity tolerance is expected to have a positive effect on the dimension strategic fit (McNally et al, 2009). It represents a person’s capacity to accept the absence of information about the range and probabilities of possible outcomes (Sherman, 1974). Concluded, the factors within the organization mindset cluster have a positive direct effect on NPPM success or dimensions of it.

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Management. Thus, it is expected that the organization mindset has a positive moderating effect on both relationships of the portfolio information cluster.

Table 4.6 Cluster variables and the factors within: Moderating cluster: Organization mindset

Cluster variable Factors within-cluster variable Positive /negative relationship with NPPM Success Significance and correlation with NPPM success Relationship with indirect variable Significance / correlation with indirect variable Type of research Moderating: Organization Mindset 1. Analytic cognitive style (37) 2. Portfolio mindset (26) 3. Ambiguity tolerance (37) 4. Knowledge sharing (20) 1. + 2. + 3. + 4. + 1. Not tested 2. Tested, α = 0.79 3. Not tested 4. Tested, Values unknown 1. / 2. / 3. / 4. / 1. / 2. / 3. / 4. / 1. Qualitative interview, three SBU’s, one company 2. Quantitative, cross-industry, 378 informants from189 firms 3. Qualitative interview, three SBU’s, one company 4.Quantitative, hierarchical multiple regression to test the framework

4.3.7 Moderating cluster: Management approach

The last moderator cluster is the cluster of the management approach. This moderator is being defined as the way organizations deal with their portfolio management processes. The factors switching team leaders among projects within the portfolio, switching team members among projects within the portfolio, stretching financial resources, and the length of the portfolio backlog all have a negative direct effect on NPPM success (McDonough & Spital, 2003). The factor number of projects people are parallel working on becomes negative from a certain point, when people are working on too many projects (McDonough & Spital, 2003). The last factor is task execution, it is focused on how portfolio management tasks are executed within the organization (Jonas, 2010). The task execution refers to the tasks of portfolio structuring, resource management, portfolio steering and organizational learning and portfolio exploitation, these tasks are seen as value creating tasks, which thus a positive direct effect on NPPM success is suggested (Jonas, 2010).

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probably lead to a better process since the methods/tools being used will only be exploited better because of the management approach that will be implemented during this process, and thus, there will be dealt better with the methods/approach, making the positive relationship stronger.

Table 4.7 Cluster variables and the factors within: Moderating cluster: Management approach

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The clusters just mentioned are shown in the path model, in figure 1. The solid lines resemble the already discussed and, in some parts, tested relations, whereas the dotted lines are suggestions this study makes. Therefore, these relationships are not tested yet and they are a suggestion for future research.

Figure 1. Path model of NPPM success

Solid lines resemble previous discussed relations; dotted lines are suggestions for future research.

5. Discussion

The findings are discussed regarding the research question of this study, followed by the main implications and recommendations for future research.

The main focus of this study was to further understand the concept of NPPM success. A systematic literature review was done to answer the following research question: “What is NPPM success, and how can it be measured?”. This has resulted in a comprehensive definition as well as a broadly accepted way of measuring NPPM success. Also, a path model was generated for showing which factors influence NPPM success.

5.1 Main findings

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Another focus of this study was the measurement of NPPM success. Because the measurements of NPPM success were mostly derived from the way NPPM success was defined, there was a lot of overlap regarding the concluded definition of NPPM success. Thus, the measurements were also mostly based on the three dimensions of Cooper et al (1997), and the dimensions added of Cooper et al (1999). Resulting in a lot of articles that used the same measurements or some variations on these measurements. The measurements that seemed to be important were the measurements already discussed in the definition of NPPM success, which resulted in the following factors being measured: 1. Value maximization, was separated into two dimensions: 1a. Average single project success, which was being measured through the factors budget, schedule, quality, adherence, and customer satisfaction of the projects within the portfolio (Teller & Kock, 2013, and 1b. Synergies, which were being measured by a multi-item scale: 1. During the project execution, development synergies between projects are rigorously exploited. 2. After project completion, exploitation synergies between projects are rigorously exploited. 3. We hardly ever have double work or redundant development (Kopmann et al, 2017). 2. Balance was being measured by evaluating projects based on the extent to which the mix of NPD projects is proportional across multiple concerns, for example, the project completion date or technical risk (Cooper et al, 1997). 3. Strategic fit measures projects in terms of the extent to which they reflect the firm’s strategy (Cooper et al, 1997). 4. Having the right number of projects is measured through a natural logarithm of the number of projects that comprise the portfolio (Kopmann et al, 2017). 5. Right time to market (no gridlock), looked at whether projects were done at time, however, there could not be found an explicit measurement for this dimension, and the last dimension: 6. Future preparedness was measured through a multi-item scale: 1. We sufficiently develop new technologies and/or competencies in our projects. 2. With our projects, we are a step ahead of our competition with new products, technologies, or services. 3. The projects enable us to shape the future of our industry (Kopmann et al, 2017). Concluding, the dimensions that have to be measured for NPPM success are all derived from the definition of NPPM success. For all dimensions, except the right time to market, explicit measurements are being found. Therefore, by having this comprehensive definition with measurements a consistent concept of NPPM success can be integrated into future research but also in NPPM practices.

Thus, when looking at the analysis regarding the definition of NPPM success and its measurements. It comes forward that Cooper et al (1997;2001) has laid a foundation for the literature of NPPM success, resulting in a broadly accepted definition with measurements that are being used for a lot of studies. So, even though the articles which were used as a base for new literature were published not very recently, they are still of very importance to the literature of NPPM success this day.

Another important part of this study was to take a look at which factors influenced the NPPM success. Three broad parts were illustrated as having a direct effect on NPPM success, these parts were generated by combining factors found in the literature into clusters. At first, the portfolio information cluster, existing out of factors that describes the information that is needed for managing the portfolio successfully. Direct effects were found of the factors on NPPM success, however, it was also suggested that the portfolio information could contribute to a better portfolio decision making process. The second main cluster consists of factors contributing to the decision-making process within the portfolio, which is also directly linked to the NPPM success. Especially the selection, evaluation and termination of projects were seen as important for the decision making for NPPM success (Müller et al, 2008; Yang et al, 2016) The last cluster is the cluster of portfolio methods/approach, stating that the methods and tools being used affect the NPPM success.

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moderating clusters, these effects have not been tested yet as well as whether the main parts are indeed of more importance than the moderating clusters.

Also, moderating clusters were integrated into this study. The three clusters of portfolio stakeholders, organization mindset and portfolio methods/approach all had factors with a direct link towards NPPM success. However, this study also suggested the moderating effects of the clusters on the relationships of the main clusters with NPPM success. The reasoning behind this is that the three main clusters influence NPPM success in a direct way since they are of main importance for the process of NPPM. However, the moderating clusters are also of importance, their direct relation with NPPM success show this importance and therefore also their connection with NPPM success. They however are put into the moderating role since they are expected to influence the main effects with NPPM success. This is because the moderating clusters are further away from the main process of NPPM success, for instance, the organization mindset, these factors have a direct linkage with NPPM success, however, the mindset probably also influences how there will be dealt with information and how decisions are being made. However, the mindset itself is not the main part of the management of a portfolio. Thus, moderating effects are expected for achieving NPPM success. These moderating effects have not been tested yet, and this possibility will be discussed further in the future research paragraph. However, the factors within the moderating clusters are already being researched within the NPPM success, thus they are not totally new for this field. By adding the possibilities of a moderating effect, the process of NPPM will become more clearer, by having a clear view of the relations influencing NPPM success.

5.2 Managerial Implications

After doing research on NPPM success, some aspects come forward which can be of use for managers integrating or improving NPPM success within organizations. At first, this study defined NPPM success and its measurements. By having a consistent manner, organizations can have a better understanding of their NPPM and its success. Also, comparisons between organizations can be made more easily when their understanding of NPPM success is more consistent. Second, this study shows the importance of the three main clusters which directly influence the success of NPPM. Therefore, suggesting that managers should give a lot of attention towards their portfolio information process, portfolio decision-making process as well as the methods and tools being used. Also, the moderating clusters affect the NPPM success, this information can be useful for managers by showing which parts do influence the relations between the main clusters and NPPM success, but it also shows that these relations are of less direct importance towards NPPM success. Thus, indicating that the main focus should at first be on the three main clusters, followed by the moderating clusters to further strengthen the relations of the main clusters with NPPM success.

5.3 Future Research

Points for future research came forward during this study. The first thing to mention is that the clusters are generated for this study and not mentioned before. Also, factors within these clusters are not only from different articles but also are studied within different kinds of studies. Some factors have been tested quantitatively whereas others are mentioned in propositions or other qualitative studies. Therefore, the factors that have not been tested yet should be researched, as well as the clusters the factors are integrated into.

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management on portfolio decision making and NPPM success. 6. The moderating effect of portfolio stakeholders on the relationship of portfolio decision-making and NPPM success and 7. The moderating effect of management approach on portfolio methods/approach on NPPM success.

Also, a positive relation of portfolio information on portfolio decision making is expected. The factors mentioned in the portfolio information do have a positive direct effect on NPPM success, however, the relationship of the variables with decision making has not been researched. It is expected that information with higher quality, which has more details and information regarding risks, will contribute to a better process of decision-making since more information can be considered. Therefore, it is necessary to further research this relation since it could be of importance since both the portfolio information as well as the decision-making are shown to be important factors for NPPM success. Thus, despite the fact that the factors within the clusters are already mentioned in previous literature, not all the factors are quantitatively tested, suggesting that these should be done. Also, the generation of the cluster is done through logical reasoning, which implicates that these could be done differently, something that future research could also further work on. Lastly, the moderating effects have not been tested, but since they will lead to a better understanding of the NPPM success process, these moderating effects should be tested.

5.4 Limitations

Although this research has been conducted in a systematic manner, where at first data was collected through a systematic search, and then analyzed by breaking down the articles in a constituent part, limitations still need to be acknowledged. At first, the study was only focused on English written articles. Thus, this study does not look beyond the research written in a different language than English. Also, only two databases were searched through, thus important articles could be missed. Furthermore, there were difficulties regarding finding relevant literature that focused on NPPM success. NPPM was mentioned multiple times, however, the success of it was mentioned not very often. Resulting in that NPPM success and NPPM performance were used as a synonym for this study. Also, it came forward that there was a lot of overlap between New Product Development and New Product Portfolio Management, where NPPM and NPD were often were mentioned together in a sentence or as synonyms. This study however focused specifically on the success of the NPPM, therefore did not further integrate parts of NPD and only used articles where NPPM (success) was mentioned as a factor on its own. Also, relevant factors could have been missed as well as relevant relationships between some factors since the clusters are generated and not from previous literature.

6. Conclusion

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