Obstacles to strategy implementation and success factors: a review of empirical literature

The purpose of this study is to identify obstacles and success factors evident from empirical studies affecting strategy implementation and to provide an overview of the empirical literature. A systematic literature review (SLR) was used to analyze thirty-five peer-reviewed empirical articles. All of the 35 research papers selected in this review use primary data gathered from the organizations studied. This study of empirical research has identified 16 obstacles that can hinder strategy implementation and 18 success factors that can facilitate implementation. This study highlights factors that are dualistic, meaning that they contain both elements of obstacles and key success factors. The dualistic factors should therefore be considered in the strategy implementation process. Research gaps are identified. They include lack of studies on how to overcome obstacles to strategy on the one hand and on employee influence on implementation on the other. The differences among industries, countries, or cultures regarding implementation have not yet been explored at any depth. The paper adds to theoretical and practical knowledge based on the systematic overview it provides on strategy implementation from 1980 until 2020. The paper enriches the practical knowledge relevant to those implementing strategies, as it captures and identifies the dualistic factors affecting strategy implementation.


Introduction
Strategy formulation has been studied and discussed in academia for half a century, but less attention has been paid to the implementation of a strategy (Aaltonen & Ikävalko, 2002;Alexander, 1985;Al-Ghamdi, 1998;Noble, 1999a). Unlike strategy formulation, strategy implementation is extremely difficult and its research history has been seen as fragmented and eclectic (Blahová & Knápková, 2010). Strategy implementation, nevertheless, is seen as a very important field having a crucial influence on organizations and their performance (Hrebiniak & Joyce, 1984). Implementation is also fundamental for the effective functioning of any organization and for a business strategy to succeed (Hrebiniak, 2006;Schilit, 1987) and can be a crucial element for creating a competitive edge, which is the core aim of any strategy formulation and implementation (Giles, 1991). Multiple scholars have consequently called for more research on strategy implementation to fill the identified knowledge gap (Atkinson, 2006;Beer & Eisenstat, 2000;Noble, 1999a). Although attention of academics has increased on strategy implementation over the last STRATEGIC MANAGEMENT, Vol. 26 (2021), No. 2, pp. 012-030 decade, managers are still facing remarkably similar problems concerning implementation (Hrebiniak, 2013).
Research has shown that a relatively small percentage of planned strategies in organizations are implemented (Mintzberg & McHugh, 1985) and too many strategies seem to fail in the implementation stage because either implementation is poorly managed or has not taken place. Therefore, scholars have underlined the importance of avoiding implementation barriers and pitfalls, since most strategies falter during implementation (Allio, 2005). It is not an overstatement to say that if the strategy formulated never gets implemented, the time, resources and capital of the company have been wasted. This is, for instance, highlighted by Olson, Slater and Hult (2005. p. 47.) who state that "doing" is much harder than "dreaming." Hrebiniak (2006) agrees with Olson et al. (2005), as he emphasizes that managers know how to plan and formulate a strategy, but not how to implement it. Studies have shown a very high failure rate of strategy implementation, ranging between 50% and 90% (Kaplan & Norton, 2001;Miller, 1997). A more recent study suggested that some of the evidence supporting these percentages is outdated, fragmentary, or lacks scientific rigor and, therefore, numbers should be taken with caution (Cândido & Santos, 2015).
Differences between strategy implementation and strategy execution are not so clear in the literature, as many scholars use the concepts as synonyms (Hrebiniak, 2006). For instance, Li, Guo-Hui and Eppler (2010) report in their research that there seemed to be a consensus of using strategy implementation as a key word in the field of strategy implementation/execution, and that few generally use strategy execution concept (Li et al., 2010). Therefore, in this study, strategy implementation and execution will be used synonymously, in line with Hrebiniak's (2006) and Li et al. (2010) conclusion.
As depicted in Figure 1, the strategic management process can be described in three main phases: formulation, strategy implementation, and evaluation (David & David, 2013). Inside these phases, the authors identified the following seven steps that have to be completed during the process: developing the vision and the mission for the organization, scanning the internal and external environment, setting objectives, choosing strategies, and implementing and evaluating its performance.

Figure 1
Model of the strategic management process (the strategy implementation phase is bolded to underline that it is the subject of this article). Source: David & David, 2013, p. 61 The first phase of the strategic management model (i.e., formulation) has been well studied (Miller & Friesen, 1978;Mintzberg & Lampel, 1999;Pettigrew, 1992) as has the role of structure and the strategy process (Galbraith & Nathanson, 1978;Noble, 1999b). The third phase, strategy evaluation, has also been studied by a number of scholars, including Daft and Macintosh (1984), Littler, Aisthorpe, Hudson and Keasey (2000), and Simons (1994). Concerning measurement and evaluating strategy performance, which can be seen as part of the strategy evaluation method, a number of studies have also been carried out. Kaplan and Norton are among the scholars focusing on this aspect, but their emphasis has mostly been on the balanced scorecard, which is widely used to map, measure, and monitor business or corporate strategy (Kaplan & Norton, 2000, 2004. The second phase, strategy implementation, is understudied in the literature. A call has been made by mangers for strategy implementation guidelines (Hrebiniak, 2006). To respond to this call, scholars have introduced frameworks and conceptual models of strategy implementation (Brenes, Mena & Molina, 2008;Hrebiniak, 2013;Okumus, 2003;Pryor, Anderson, Toombs & Humphreys, 2007;Safdary et al., 2014). However, most of these frameworks are conceptual and descriptive and have limited practical implications (De & Janssen, 2001;Engert & Baumgartner, 2016).
The 5Ps model of strategy implementation, suggested by Pryor et al. (2007) is a tool that can help organizations to achieve implementation as a core competency (See Figure 2). The 5Ps model has five critical elements surrounding the concept of strategy implementation: purpose, principles, processes, people, and performance. The model also focuses on sub-elements or specific activities and functions, such as structures, systems, leadership behaviour, human resource policies, culture, values, and management. To ensure successful strategy implementation, the 5Ps model provides an integrated structure, which needs to be fully aligned for maximum efficiency (Pryor et al., 2007). In this study, the 5Ps model is used as an analytical framework to identify success factors and obstacles facilitating or hindering strategy implementation. The 5Ps model was chosen because not only is it conceptual but also based on integration of theory and experience from diverse business disciplines, providing an effective and pragmatic approach for strategy implementation (Pryor et al., 2007). Source: Pryor et al., 2007, p. 8. At least four literature reviews on strategy implementation have been carried out, i.e. by Noble (1999a), Li et al. (2010), Alharthy, Khan, Rashid & Pagliari (2017) and Tawse and Tabesh (2020). First, Noble (1999a) performed a mixedconceptual and empirical implementation-related review and found implementation to be a complex phenomenon and that strategy formulation and implementation are intertwined processes. Noble's findings showed three main themes of enquiry. The first theme concerned managers' behaviour, especially when managers may engage in selfinterest behaviour that can impair the implementation. The second theme covered strategic consensus among managers and key external stakeholders. The third theme related to involvement of employees as early as possible in the process, the adaptation of businesses and their culture to the changing environments, as well as managers' leadership styles (Noble, 1999a). Second, Li et al. (2010) conducted also a mixed study of both conceptual and empirical papers, largely supporting the conclusions of Noble's (1999a). Their findings indicate that people issues received the most attention, and most of the studies explored middle managers and their influence on strategy implementation. The reviewed studies present an unclear picture of the relationship among communication, commitment, and consensus, which has been researched by a number of scholars (Alexander, 1985;Floyd & Wooldridge, 1997;Guth & Macmillan, 1986;Rapert, Velliquette & Garretson, 2002). Very few studies focus on the effect that the relationships among different strategy levels have inside a company, such as business and/or operational level on implementation. In addition, there seemed to be a trend in studies towards developing frameworks and model-based approaches to strategy implementation (Li et al., 2010).
Third, Alharthy et al. (2017) explored current research and a systematic search process was carried out ending with 47 papers related to the topic. As in both Li et al. and Nobles' research both conceptual and empirical papers were analysed. They found out that many organizations could not maintain competitive advantage despite having strong strategy in place. This was mostly due to lack of achievement at the strategy implementation stage as leaders and top management did not pay enough attention to the implementation. Many other factors were also neglected, and the paper specifically stated the necessity in future research to use empirical data from organizations where strategy has been implemented (Alharthy et al., 2017).
Forth, Tawse and Tabesh (2020) performed a review of the literature studying both conceptual and empirical papers focusing on organizational factors that impact strategy implementation effectiveness. The outcome of their work was an introductory framework which builds on the previous findings of Noble (1999a) identifying conditions of strategy implementation effectiveness. These conditions are the structural and interpersonal capabilities managers may employ to be able to select and carry out managerial actions that create the conditions for strategy implementation effectiveness (Tawse & Tabesh, 2020).
The purpose of this study is to identify obstacles and success factors evident from empirical studies affecting strategy implementation. To address the issue, this study provides an overview of major empirical research on strategy implementation obstacles and success factors from 1980 until 2020. It identifies the major obstacles hindering strategy implementation as well as the key factors for successful implementation with a focus on identifying possible gaps in the literature. As the literature is fragmented and still in development, scholars have called for additional empirical studies to explain successful strategy implementation in different types of organizations, industries, and businesses (Baumgartner, 2014;Klettner, Clarke & Boersma, 2014). Empirical papers used in this literature review have been listed (See Table 1) and the empirical papers used in the four reviews done by, Noble (1999), Li et al. (2010), Alharthy et al. (2017) and Tawse and Tabesh (2020). The structure of this article is as follows: Section 2 describes the method and analysis employed for carrying out this literature review. The results are presented and discussed in Section 3. Section 4 covers the conclusion.

Research method
The purpose of this article is to review the literature on empirical studies on strategy implementation using existing research to create new knowledge, as proposed by Torraco (2016). The research follows the guidelines offered by Nakano and Muniz (2018) on how to write a literature review for empirical papers. To fulfill the objective of building a standalone review of the empirical literature and identifying knowledge gaps concerning strategy implementation in organizations, relevant studies have been reviewed and analyzed. All of the 35 research papers selected in this review use primary data gathered from the organizations studied.

General database search
The method employed was to collect and analyze empirical peer-reviewed scholarly articles in the field of business strategy implementation. For this purpose, a standardized and rigorous methodology, as suggested by Nakano and Muniz (2018), was applied. It includes a useful method to build a standalone systematic literature review (SLR). The literature databases used to access the peerreviewed studies in this field were Scopus, Web of Science, and ProQuest. All searches were conducted in the search window of each database with the tools supplied and the content was displayed based on a number of criteria presented, in Table 2. The content was provided in order of relevance extracted from the titles, abstracts, and keywords of the articles.

Focused searches
The initial search results shown in Table 3 are displayed for Scopus, Web of Science, and ProQuest databases. The numbers displayed in the Database column in Table 3 refer to the search string used for each database; the search strings are: Search string 1; "Strategy implementation" AND "obstacle" Search string 2; "Strategy implementation" AND "lever" Search string 3; "Strategy implementation" AND "barrier" Search string 4; "Strategy implementation" AND "key success factor" Search string 5; "Strategy implementation" AND "failure" During the second selection, the following criteria were used for inclusion of papers: 1. Empirical studies 2. Articles published in academic journals 3. Research methods described 4. Content focused on strategy implementation obstacles and/or success factors At this stage, 20 papers were included. This means that paper not containing evidence of strategy implementation obstacles and/or key success factors were outside the scope of this article. In other cases, the papers were outside the scope of this review if the content was not in English, even though the titles and abstracts were, or if they provided only short overviews rather than research outcomes and/or had very limited or no discussion about research methods.

Additional searches through references
To ensure access to articles, both open source and non-open source, the Icelandic National Library database was used, but it provides access to articles through databases such as EBSCOhost, ProQuest, Scopus, and Web of Science. In the case where access was not granted via the national database, access to articles was bought through the University of Iceland or Reykjavík University. Backward and forward snowballing technique, using the reference list and citations, was applied to identify new papers as recommended by Wohlin (2012). An additional search of the literature was carried out in accordance with a technique recommended by Webster and Watson (2002; i.e., identifying additional references from key articles). Some of the articles referenced research and articles outside of the search scope but focused on similar topics according to their title, authors, and journals in which they were published. Therefore, 35 articles were included in the final review: 20 based on a focused search and 15 from the additional search.
The search engine Google Scholar was used to find these 15 articles.

Analysis
In step one, the context of the articles was analyzed based on the information available in the articles themselves. In step two, the content of the selected articles was analyzed based on the guidelines on how to write a literature review for empirical papers (Nakano & Muniz, 2018). In step three, analytical tools were used. The analysis was conducted in three consecutive steps: Step One: Research context Step Two: Research objectives, findings, and methodology Step Three: Analysis of obstacles and success factors  The 35 articles were categorized into two main groups: a) research focused on strategy implementation obstacles and b) research focused on strategy implementation success factors.


The content of those research items was analysed in Excel and using the Mind Map software.

Results
As Table 4 reveals, the articles analyzed in step one deal with different contexts and external environments. The analysis was based on the type of organization studied, including private companies (Co), public organizations (PO), companies owned by either private and public owners, public/private/partnerships (PPP), and/or non-profit organizations (NPO). The studies have also been conducted on different levels within the organizations (i.e., corporate or business level or lower operational levels). Furthermore, different perspectives have been studied related to strategy implementation. Those taking part in strategy implementation can be senior and top managers, middle or lower managers, employees, or a mixture STRATEGIC MANAGEMENT, Vol. 26 (2021), No. 2, pp. 012-030 of all positions. Top and senior managers can be presidents, owners, board members, and/or highranking executives, such as chief executive officers (CEO), chief finance officers (CFO), and chief operating officers (COO). In accordance with the guidelines proposed by Nakano et al. (2018), the structure of Tables 5 -8 is based on when the relevant articles were published, author(s), research objective(s), findings, and methodology. The review included articles published between 1980 and 2020; each of the four tables covers 10 years.
In the early work of various scholars (see Table  5) related to strategy implementation, the focus was on understanding and explaining the concept of strategy in organizations in terms of how it enhances competitive advantage and improves a company's performance (Bourgeois, 1980;Hrebiniak & Snow, 1982;Nutt, 1983;Waterman et al., 1980;Wooldridge & Floyd, 1990). In the 1980s, research also focused on obstacles to strategy. Two of these early studies identified a list of obstacles that must be addressed in the formulation process, as a poor strategy formulation approach can lead to strategy obstacles later in the process (Hambrick & Canella, 1989), whereas others need to be addressed in the implementation stage (Alexander, 1985;Wernham, 1985). As can be seen in Table 5, studies of middle management emerged concerning how implementation factors influence middle management (Wernham, 1985) and how middle management can influence implementation (Guth & Macmillan, 1986). play.
2 Bourgeois (1980) To identify the importance of consensus, goals and means.
Strategy makers should concentrate on reaching consensus rather than focusing on goals when formulating a strategy.
Questionnaires sent to top management in 12 public corporations.
Unit would benefit for having managers with marketing and sales experience that are willing to take risks and have greater tolerance to ambiguity.
Mailed survey within 58 strategic business units (SBU) within eight Fortune 500 firms. 4 Wernham (1985) To study how factors influence the implementation of strategy among senior and middle management.
Factors included were the availability of resources, top management support, history of past implementation, and size of implementation unit.
Case study in one public company (British Telecom). Semi-structured interviews conducted.

Alexander
To identify strategy implementation obstacles faced by top management.
Major strategy obstacles were, lack of time allocated, unexpected problems, lack of coordination, and activities were not effective.
A questionnaire was distributed to 93 top executives. Follow-up interviews with 21.
6 Nutt (1986) To determine if different tactics affect implementation.
Four types of implementation tactics were used in 93% of cases (intervention, persuasion, participation, and edict).
Self-report study of 90 middle managers. Written real-life cases. 7 Guth & Macmillan (1986) To examine the scope and effects of strategy intervention.
Middle managers who believe their selfinterest is compromised can redirect strategy, delay, and sabotage or reduce quality of implementation.
Multi-case study with 91 case studies. Data collection based on in-depth interviews. 8 Govindarajan (1988) To study budget evaluative style and competitive strategy.
Organization structure, control systems, managers' characteristics, and firm focus are effective in achieving strategy implementation.
Questionnaire used for data collection from 24 firms on the Fortune 500 list.
9 Hambrick & Cannella (1989) To study how to convert a new strategy into competitive success.
Keys to implementation are, broad participation at the formulation stage, carefully assessing obstacles, making early use of levers, selling strategy to stakeholders, and responding as events arise.
A case study of one company. Interviews with top management.

Authors
Objective Findings Methodology 10 Wooldridge & Floyd (1990) To study the strategic involvement of middle managers.
CEOs believe that middle managers make a meaningful contribution. Middle managers expect and desire strategic direction. Involvement by itself does not cause commitment.
Interviews and questionnaires were used to collect data from 157 respondents in 20 organizations.
11 Walderseel & Sheather (1996) To study if and how the type of strategy implemented influences the implementation.

Effects of strategy on leaders' behavior and choices of implementation actions. Results
show that strategic context influences managers' implementation intentions.
Data were collected through surveys and assignments. A simulation was used to test managers. Case analysis was also used. 12 Al-Ghamdi (1998) To replicate Alexander's (1985) study of strategy implementation.
Six major strategy implementation obstacles were identified. Communication, management support, and effective information systems Surveys used to collect data from 24 companies. were key to successful implementation.
Individual responsibilities for implementing change are not clear, senior managers withdraw when implementation begins. Lack of understanding of implementation.

Source: The authors
Between 2000 and 2009 (see Table 7), several authors presented models and frameworks based on the empirical data collected. For instance, Okumus (2001) integrated 10 key variables into a conceptual framework of implementation that was later developed into an implementation model of strategic content, context, process, and outcome (Okumus, 2003). In their conceptual framework of key dimensions of strategy implementation, Brenes et al. (2008) developed a framework based on data collected in 81 organizations in Latin America. Hrebiniak (2006) studied obstacles and how to overcome them, offering a conceptual framework on key decisions and how to translate strategy into short-term metrics and to implement it in the organizational context. Scholars continued to collect empirical data on strategy implementation obstacles and success factors throughout the decade. A study using interviews, observations, and document analysis. Case study of two hotel groups.
16 Rapert et al. (2002) To study if the frequency of communication between marketing and top management has a positive effect on strategic consensus.
Identified six strategy implementation obstacles: poor vertical communication and coordination across functions, topdown laissez-faire senior management style, unclear strategy, and conflicting priorities.
Qualitative and quantitative research. A survey was mailed to 1,000 CEOs and marketing executives with 322 responses. Followed by 30 in-depth interviews.
17 Heide et al. (2002) To identify barriers to successful strategy implementation.
Different kinds of communication problems were key barriers to strategy implementation.
Case study. Data were collected from business unit staff members through 42 structured interviews. 18 Aaltonen & Ikävalko (2002) To identify strategy implementation obstacles in service organizations.
Important to align systems and structure with strategy. Frequent vertical communication and strategic consensus can improve organizational performance.
Qualitative research. A case study of 12 service organizations with 298 interviews.
19 Shah (2005) To identify strategy implementation obstacles helping organizations to implement strategy more successfully.
Companies most frequently experienced 11 obstacles during strategy implementation.
Data collected with a questionnaire from 145 managers in 35 industries.
20 Schaap (2006) To study the relationship between leadership behavior and successful strategy implementation.
Frequent communication up and down organization structure enhances consensus and fosters shared values. Plans must be developed and tasks, timeframes, and responsibility must be specified.
Close-ended questionnaire was used and mailed to the participants and 120 responded. To identify and evaluate factors that play a significant role in strategy implementation.
A strategy implementation framework that consists of internal and external contexts, and processes and outcomes proposed.
Survey of fixed and open-ended questions. Panel discussion used. Data were collected from 433 managers. 22 Crittenden & Crittenden (2008) To determine why strategic planning efforts and implementation fail.
Successful implementation is based on various strategic elements, such as supportive policies and systems. Most systematic strategy implementation needs more integrative methodology.
A mixture of primary and secondary data were collected from 29 organizations.
23 Brenes et al. (2008) To measure the effect of key variables on successful implementation.
Five key success factors were identified for implementing a business strategy successfully.
Survey questionnaire were mailed and 81 companies responded.

Source: The authors
In Table 8, strategy implementation and how it affects a company's performance can be seen as the main focus of studies between 2010 and 2020. For instance, Sorooshian et al. (2010) examined the relationship between strategy implementation and the performance of small-and medium-sized manufacturing companies and found that leadership style, structure, and resources supporting implementation affect financial organizational performance. Another study found that inadequate leadership and employees' reluctance to share their knowledge have a negative effect on organizational performance (Cater & Pucko, 2010). Furthermore, other issues affecting the organizations' performance indicators concerning implementation include not carrying out comprehensive analysis and planning and a lack of training in combination with low levels of employee motivation (Köseoglu et al., 2018). Authors continued to bridge the knowledge gap by studying factors affecting poor implementation (Mollahoseini & Ahmadkhani, 2012;Pella et al., 2013), success factors, and the importance of organizational culture and how it can contribute to successful strategy implementation (Alamsjah, 2011;Al-Kandi et al., 2013). To identify obstacles of strategy implementation and how they affect performance.
The biggest obstacles having negative effect on performance are inadequate leadership and employees' reluctance to share their knowledge.
Questionnaires sent to managers and board members in 172 companies.
25 Sorooshian et al. (2010) To study the relationship between strategy implementation and performance.
Strategy implementation drivers, such as leadership, structure, and human resource management, contribute to a company's performance.
To study how and if an executive style determines strategy implementation and performance.
The failure to align SME executive style and strategy leads to performance loss. Alignment is key when it comes to driving change and innovation.
Data gathered from 241 companies on strategy and 303 companies on executive style.
To identify strategy obstacles.
Number of obstacles such as organizational, planning, managerial, staff, and environmental obstacles identified.
Study using interviews, focus groups, and questionnaire, with 205 respondents. 29 Al-Kandi et al.
To identify what determines successful strategy implementation.
Identification of process and personnel, project, religion, and organizational factors.
Study using questionnaire with a sample of 120. To verify to what extent corporate strategy is reflected in lower managerial levels.
Strategy implementation is most lacking on an operational level and lack of training of employees affects their awareness of the corporate strategy.
Research conducted in 30 Polish enterprises by questionnaire.
33 Köseoglu et al. (2018) To examine potential barriers to the implementation of strategic decisions.
Identified 41 barriers to implementation and at least 20 of them had influence on performance and operation.
Research conducted in Turkish hotels by questionnaire with 118 responses. 34 Tawse et al.
To study top managers' struggle with the transition between strategy formulation and implementation.
Top managers tend to focus on strategy formulation and planning but fail to embrace the problem solving and complexity of implementation.
Research based on interviews with CEOs.
35 Köseoglu et al. (2020) To study how managers perceive strategic management process.
Managers in this study agree that communication and people management are the key success factors in strategy implementation.
Study using interviews with 21 managers. Table 9 summarizes the research methods employed for all articles reviewed. The majority of studies gathered data using questionnaires, 12 studies used interviews, and 4 studies employed mixed methods of both interviews and questionnaires. Other studies employed focus groups (Mollahoseini & Ahmadkhani, 2012), simulations (Walderseel & Sheather, 1996), role play (Corboy & O'Corrbui, 1999), observations (Okumus, 2001), panel discussions (Hrebiniak, 2006), and self-reporting real-life cases (Nutt, 1986). Some of the studies used one or more researched methods. In some cases the limitation of the research was not outlined in the reviewed articles. Nevertheless, identified limitations were related to the data collection methods, which in many cases were based on a single method, revealing a lack of triangulation (Cater & Pucko, 2010;Govindarajan, 1988;Heide et al., 2002;Walderseel & Sheather, 1996). Validity and generalization of some of the studies are limited based on the small sample used (Heide et al., 2002;Schaap, 2006). Some of the studies use selfreported data collection methods, which can be biased based on perspective (Cater & Pucko, 2010;Håkonsson et al., 2012).

Analysis of obstacles and success factors
Step three, as described in Section 2.4, focuses on the analysis of the content of the papers. First, success factors: Many of the obstacles and the success factors identified can simultaneously be viewed as obstacles hindering implementation and factors necessary for successful implementation.
Based on this analysis related factors affecting strategy implementation are paired (see the grey area and the arrow in Table 10) and the articles that reference each factor are reported in parentheses.  Pryor et al. (2007). (Article numbers in Table 5 -8 are given in parentheses)

People
Limited commitment and understanding (13,19,28) <---> Shared understanding (2,9,10,16,18,20,31,35) Inadequate staff capabilities (5,14,17,19,24,32) Performance Limited alignment and coordination (5,12,14) <---> Alignment and integration (1,15,18,22,27,31) IT do not support or monitor strategy (4,5,12,19,24,33) Monitoring strategy (22,35) Staff accountable for task and action (20,23,26,31) Tying awards with implementation (18,20,22) Source: The authors Figure 3 shows the obstacles and the success factors affecting strategy implementation grouped graphically based on the five elements of purpose, principles, process, people, and performance from the 5Ps model (Pryor et al., 2007). These five elements in Figure 3   The following discussion centres on the dualistic factors identified in Table 10 presented in Figure 3. The first of the dualistic factors in the purpose element is leadership, which focuses on leadership support, motivation, and style influencing implementation. Shah (2005) underlined that commitment and support refers to involvement and overall responsibility of top management, which should be accountable for the implementation process. This responsibility, according to Shah, cannot lie anywhere else in the organization, as top managers are accountable for the performance of an organization as a whole. The second dualistic factor brings forth the importance of defining objectives, setting goals, and linking them to the business strategy and the competitive environment as vital aspects related to implementation (Beer & Eisenstat, 2000). Setting key performance indicators is not only inadequate in many organizations but is also seen as challenging, and this is even harder to accomplish at lower levels in organizations (Aaltonen & Ikävalko, 2002). The lack of indicators, objectives and goal setting can, therefore, hinder implementation. Employees often do not have a road map for implementation, as there are no clear key indicators for the performance of each person or position (Pella et al., 2013). The third dualistic factor is management style, which has been identified in a number of studies. Wernham emphasized that top management support was important for successful implementation and is one of the rare points on which most experts can agree (1985). Beer and Eisenstat (2000) indicated that frequent absence of senior management during strategic decision-making would affect the implementation. Some studies have also shown that senior management tends to withdraw when implementation begins and their lack of support can consequently affect the implementation (Corboy & O'Corrbui, 1999). The fourth dualistic factor highlights the importance of having a clear strategy for successful implementation. A number of researchers have come to this conclusion (Alamsjah, 2011;Beer & Eisenstat, 2000;Cater & Pucko, 2010;Köseoglu et al., 2018). Hrebiniak (2006) stressed that poor or vague strategy limits the implementation effort and therefore is a major obstacle as good execution cannot overcome various shortcomings of a bad strategy or poor implementation efforts.
There are two dualistic factors in the principle element, change management and culture. Change management was identified by Hrebiniak (2006) and he determined that the inability to manage change and the importance of reducing resistance to change was the topmost challenge and obstacle for managers. Cater and Pucko (2010) found that managers lack capabilities to implement change management in Slovenian companies, which supports Hrebiniak's conclusion. Crittenden and Crittenden (2008) found that company internal culture plays a vital role as a driving force in successful implementation. They also found that different cultures between silos can have a negative influence on implementation (Crittenden & Crittenden, 2008). The importance of culture has been identified as a major obstacle or success factor by a number of authors (Brenes, 2008;Heide, 2002;Köseoglu et al., 2018;Sorooshian et al., 2010).
The first dualistic factor in the process element is communications, which highlights the importance of frequent and clear communication and the issues which can arise with a lack of communication. Alamsjah (2011) found that it is not enough just to have a clear strategy it needs to be communicated through the organization and be translated into execution plans. Rapert et al. (2002) highlighted that vertical communication and shared understanding play a key role in the process. Similar findings are discussed by Schaap (2006) on the importance of communications to help employees understand the strategy being implemented. The second dualistic factor in the process element is time and importance of timeframes being set. A number of studies have shown the importance of realistic timeframes, as strategy implementation takes more time than commonly allocated (Al-Ghamdi, 1988;Alexander, 1985). Al-Kandi et al. (2013) indicated that, if timeframes were set, they had to be followed up with detailed planning and implementation must be put ahead of other managerial commitments. The resource factor is the third factor in the process element. Crittenden and Crittenden (2008) found it was not only important for companies to have access to resources but also to decide when and where to allocate them, whether it is money, people, time, or capabilities.
The only factor in the people element emphasizes that commitment and shared understanding of the strategy influences successful implementation (Rapert et al., 2002), but so does the importance of building up consensus in the implementation process to foster shared attitudes and values (Schaap, 2006).
Last, performance element has one dualistic factor, which is alignment and coordination which has been identified by a number of scholars. Strategy alignment is the important process of linking the organization's structure and resources with its strategy and external business environment (Aaltonen & Ikävalko, 2002;Al-Ghamdi, 1998;Beer & Eisenstat, 2000;Håkonsson et al., 2012;Okumus, 2001).

Conclusion
Research on strategy implementation is still in its early days, with a limited number of empirical studies completed. Most of the effort has historically been focused on strategy formulation and process and less on strategy implementation, let alone studies grounded in empirical data.
The findings suggest and synthesize that empirical research has so far identified 16 obstacles that can hinder strategy implementation and 18 key success factors that can facilitate implementation. This study also draws the attention to, and highlights, factors that are dualistic, meaning that they contain both elements of obstacles and key success factors. The dualistic factors, or elements, should therefore be considered in the strategy implementation process.
The theoretical implication of the study is that it provides an overview of major empirical research concerning strategy implementation obstacles and success factors conducted from 1980 until 2020. Older studies providing the review of the literature reach back to 2010. Furthermore, previous literature reviews combine a mixture of conceptual and empirical research, as presented in Table 1, and have left out number of empirical papers that are included in this particular review. Therefore, this systematic review offers a more holistic overview of implementation obstacles, success factors, and dualistic factors, than previous studies.
The paper also enriches the practical knowledge on implementation obstacles, success factors, and dualistic factors which are of relevance for those implementing strategies, such as managers and other implementers. Another benefit offered to practitioners is how these factors are categorized based on the five critical elements presented in the 5Ps model including the concepts of strategy implementation, namely: purpose, principles, STRATEGIC MANAGEMENT, Vol. 26 (2021), No. 2, pp. 012-030 processes, people, and performance.
Ample room exists for further study on strategy implementation obstacles and understanding how to overcome them, a problem that seems to occur repeatedly in the strategic process. Studies that combine the identification of obstacles and uncover workable solutions are lacking. Additionally, a substantial lack of studies exists on employee influence on strategy implementation, both positive and negative aspects, which may be crucial to gain a better understanding of why and how so many strategy implementation projects fail, or succeed in some cases. Strategy implementation literature could benefit from a greater number of studies employing observation, focus groups, and panel discussions, which could add value and new perspectives to the understanding of the topic in question. The differences among industries, countries, or cultures regarding implementation have not yet been explored at any depth.
One of the limitations to this study is that selection bias of authors and subjectivity may have influenced the exclusion of articles but several techniques were used to mitigate this risk. This review relies on databases that support keyword search, where search strings must be identifiable. This approach used could overlook important literature and restrict accessibility of sources. Furthermore, this review article focuses solely on full-text articles published in English and last, a small number of articles analysed limits the generalizability of the findings.SM