A systematic review of lean simulation games in the construction industry

ABSTRACT

Lean philosophy has garnered attention in the construction industry world-wide and lean simulation games have arguably played a vital role in lean’s uptake by the architecture, engineering, and construction (AEC) industry. Although numerous lean simulation games are already being used extensively both in industry and academia, there has been, as yet, no systematic investigation in this area. In this context, this paper reports a systematic literature review to analyse existing lean simulations and games. Relevant databases were identified, and a search strategy was devised to uncover relevant literature. Peer-reviewed papers were vetted according to a set of pre-determined inclusion and exclusion criteria. Following the screening process, 52 documents were identified from the databases. From the final set of papers, 96 games in total were identified. The papers were analysed for a variety of factors including distribution along a timeline, database homes, authorship and countries of origin using social network analysis, and depth of discussion of particular simulations. Findings showed that the popularity of lean simulation games in the construction sector has grown in recent decades. According to our systematic review of the literature, the International Group for Lean Construction (IGLC) serves as a significant contributor to the emergence and dissemination of new and existing lean games and simulations. The analysis also indicated that most contributions have originated in the United States. Our social network analysis also indicated that a few key authors collaborate extensively, while others in the periphery are beginning to publish and collaborate.

KEYWORDS:

• Lean
• construction industry
• simulations and games
• systematic review

Introduction

There has been a growing interest in ways to reinvent the Architecture, Engineering and Construction (AEC) industry in terms of digitalization, innovative technologies, and new construction techniques in order to create technological, cultural, strategic, and economic transformations within the industry (McKinsey, 2018). To this end, recent decades have witnessed an increased call for the adoption of lean concepts as a possible path forward (Abdelhamid & Salem, 2005; Koskela, 1992; Koskela, Ferrantelli, Niiranen, Pikas, & Dave, 2019, 2002; Rybkowski & Forbes, 2016). The roots of lean concepts and principles are embedded deeply within the Toyota Production System (Liker, 2004). The efforts and struggle of lean champions in developing and applying these principles have brought remarkable transformation in the manufacturing domain.

A similar kind of transformation in the AEC sector is dependent on how these lean concepts and principles are being understood, applied, and practiced by stakeholders associated with the AEC sector. While various terminologies, philosophies, and interpretations of the lean concept have been discussed in the literature, they are arguably only partially understood and applied (Forbes, Rybkowski, & Tsao, 2018).

Within the context of Bloom taxonomy, lean educators (both at universities and those serving the AEC industry) typically aim to not only impart to students a foundational understanding of lean, they also structure coursework to engage students at multiple levels, including remembering, understanding, applying, analysing, evaluating, and creating lean concepts and principles (Bloom, Engelhart, Furst, Hill, & Krathwohl, 1956; Rybkowski, Forbes, & Tsao, 2020). Glenn Ballard and Gregory Howell, among other lean pioneers, began exploring the potential of games and simulations in this context (Rybkowski, Forbes, & Tsao, 2018).

In the last decade, there has been a growth spurt in the adoption of lean simulations and games in academia and the AEC sector. Lean simulation games have shown themselves to be integral to the transferral of lean principles as is evidenced by their consistent inclusion at conferences organized by bodies such as the Lean Construction Institute (LCI) and the International Group for Lean Construction (IGLC). Lean construction courses offered at universities use the facilitation of serious games and simulations to impart an intuitive understanding of lean principles (Hamzeh & Albanna, 2019; Nofera, Abdelhamid, & Lahouti, 2015; Pellicer & Ponz-Tienda, 2014; Rybkowski et al., 2018; Tsao, Alves, & Mitropoulos, 2012). The prevalence and growth of lean simulations suggests they will likely continue to serve as a prominent vehicle to impart lean concepts and principles to stakeholders. Rybkowski, Alves, and Liu (2021) documented the emergence of an international, experimental lean simulation community that has been expanding across the world using an on-line format, resulting in a collaborative forum called Administering and Playing Lean Simulations Online (APLSO).

A review of extant papers that focus on lean games and simulations in the construction domain would be valuable for the lean community and can enhance the potential of lean simulations, while suggesting future trends. In this paper, we present a systematic review of the literature on lean simulations and games in the construction industry. With a large and rapidly growing body of knowledge on lean games and simulations, different perspectives such as number of publications, collaboration between authors, levels of discussion etc. are put forward to analyse existing studies in this area. Because simulations often serve a critical role in bridging the gap between lean theory and its applications, the intent of this review is to systematically analyse the existing state of serious games and simulations developed for and being used by those who teach lean construction both in industry and academia, and suggest potential areas for improvement of lean simulation games.

This paper is structured as follows: we initially focus on the theoretical background of simulation research through ideas and concepts related to lean construction, as well as the potential, structure, and terminologies of simulation games used to support this study. We also discuss the strategy adopted for identifying relevant literature in the research method section. Based on findings of the literature search, the following section examines selected papers in terms of eight parameters. Finally, a summation of our findings and recommendations for future research are presented in the Conclusion.

Theoretical background

Lean construction

Lean concepts have evolved since they entered the construction industry in the 1990s. Various definitions of ‘lean’ have been proposed over the years by those pioneering its applications to projects in the AEC sector. One such definition was proposed by: Howell and Ballard (1998, p. 3): Implementing lean means adopting a ‘project-as-production-system’ approach to construction, defining the objective in customer terms, and decentralizing management to maximize throughput and reduce inventories. L. Koskela, one of the early pioneers of lean construction who brought the Transformation-Flow-Value generation (TFV) model of production into the construction industry, defined lean construction as a way for design production systems to minimize waste of materials, time, and efforts in order to generate the maximum possible amount of value (Koskela, Howell, Ballard, & Tommelein, 2002, p. 1).

Additionally, Rybkowski and Forbes (2016) defined Lean construction as reducing waste and adding value using continuous improvement in a culture of respect – comprising the four essential concepts of waste, value, continuous improvement, and respect. This definition has been adopted for this paper.

Simulation games

In contrast to entertainment ‘gaming’, goal-oriented simulations have an explicit educational objective and are not designed to be played solely for entertainment (Abt, 1970; Wouters, Tabbers, & Paas, 2007). They are used for training, planning, and problem-solving. There has been a terminological ambiguity in the terms; for example, simulation, game and simulation game, are terms commonly used in studies about game-based learning.

A simulation has been defined as a learning approach in which an artificial environment is created that replicates or imitates complex real-world systems, processes, or environments (Moizer, Lean, Towler, & Abbey, 2009; Narayanasamy, Wong, Fung, & Rai, 2006). Using simulations, the existing behaviour of the system can be studied, and a prediction of possible outcomes is made. A simulation can be performed either physically or by using a digital platform – the latter being more prevalent in many applications (Ellington, 2002).

Games, on the other hand, are systems in which actors are engaged in various interaction modes. Games include competition, collaboration, cooperation, conspiracy, etc. under a predefined context and with a set of rules/procedures. Games are not intended to replicate real-life but are used for entertainment value (Harteveld, 2011).

A simulation game represents a hybrid comprising features of both games and simulations (Duke & Geurts, 2004; Smale, Overmans, Jeuring, & Grint, 2016). The intent of games is typically to engage players in an entertaining way, whereas simulation helps to train and develop the skills of the operator. The objective of a simulation game is to instruct, educate and entertain players. As explained by Shapiro (1970) and Duke and Geurts (2004), if an artificial simulation model is played by human participants and designed so that resulting human behaviours are considered a primary aim of the system, the model is called a simulation game. In simpler terms, a simulation game is performed to simulate a social system’s context (Klabbers, 2009). Mayer (2009, p. 1) defines simulation games as experimental, rule-based, interactive environments, where players learn by taking actions and by experiencing their effects through feedback mechanisms that are deliberately built into and around the game.

Simulation games can be played in physical or computer-based formats. As stated by Shou, Wang, and Wu (2021a), physical games provide hands-on experimental learning by allowing players to practise physical operations in a simulated environment. By fully immersing students or trainers in the simulation process, hands-on simulation is the most widely used technique for education and training that introduces learning in a fast-paced, engaging and interactive manner. The use of computer-based techniques such as Monte Carlo simulations, BIM or programmes such as DES and ABS to generate a simulated visual environment through animation is referred to as a computer simulation game (Standridge, 2001). It has been observed that a hands-on approach to simulation games engages players more and allows them to experience the benefits of lean tools physically while computer-based simulations may create a sense of isolation (Sacks & Goldin, 2007; Sacks, Esquenazi, & Goldin, 2007). Computer-based simulations are also time-consuming and expensive to develop and may require extensive technical skills to develop and to play (Cant & Cooper, 2014; Shou et al., 2021a). Many lean construction educators appear to prefer to facilitate simulations as hands-on physical activities, thereby establishing the efficacy of this method in terms of its ability to improve learning (Rybkowski et al., 2021).

Simulation games as a pedagogical tool for teaching lean

Existing literature in the domain of lean construction highlight ‘lack of understanding / knowledge on lean and complexity of lean philosophy and terms’, ‘lack of personnel training’ and ‘employee resistance to change’ as possible impediments to the construction industry’s adoption of lean principles (Bashir, Suresh, Oloke, Proverbs, & Gameson, 2015; Demirkesen, Wachter, Oprach, & Haghsheno, 2019; Hamzeh, Theokaris, Rouhana, & Abbas, 2017; Sarhan & Fox, 2013). Sacks and Goldin (2007) argued there is a need for training in lean techniques because continuous improvement cannot be achieved without training. The mantra to ‘learn-by-doing’ is partially fulfilled through the playing of simulation games, and as such, the method offers a way to effectively bridge the gap between lean theory and its practice.

Lean simulation games are considered to be a useful technique in the construction industry because, among other things, they transmit knowledge about numerous lean concepts in a clear, realistic, and simple manner (Hamzeh et al., 2017; Rybkowski et al., 2018). They play an increasingly crucial role in the spread of lean construction throughout the construction industry worldwide (Rybkowski et al., 2021). Developing, testing, and reporting of lean simulation games is now an established practice not only in research universities (Bhatt, Rybkowski, Kalantar, & Fernández-Solís, 2016; González et al., 2014; Howell & Liu, 2012; Jacob, Sharma, Rybkowski, & Devkar, 2021; Pollesch, Rovinsky, Alvarado, & Alves, 2017; Rybkowski & Forbes, 2016; Rybkowski & Kahler, 2014; Rybkowski, Zhou, Lavy, & Fernández-Solís, 2012, 2018; Sacks et al., 2007) but also in the AEC industry as various companies have begun to introduce lean construction concepts into construction workers’ everyday behaviours, practices, and job performance (Forbes et al., 2018; Hamzeh & Albanna, 2019; Warcup & Reeve, 2014).

Simulation games are frequently used as a pedagogical tool to assist students with limited industry experience. They are used to help employees understand site challenges in real life, teach lean philosophy, methods, and tools that address organizational and site problems and drive behavioural changes. However, they also cannot be treated as a panacea because they must be externally validated and participants still need to make a cognitive connection between the lessons imparted by a simulation and its on-site application (Rybkowski et al., 2018). Nevertheless, simulations instil confidence in those who teach and practice lean because they offer a way to test and confirm process decisions beforehand while incurring minimal risk (Rybkowski et al., 2021).

Research gap

Specific simulation games such as Parade-of-Trades, the Lego® Airplane Game (Visionary Products®), LEAPCON Simulation, Villego® Last Planner® System Simulation, and Silent Squares are popularly discussed in papers and used widely by those teaching lean in the construction sector (Forbes et al., 2018; Zofia K. Rybkowski et al., 2018). The focus of simulations in lean research publications corresponds to the increasing use of simulations to assist with lean understanding, acceptance, and implementation in sectors such as education, policy making, business, management, higher education, security, supply chain management, transportation and logistics, healthcare, and planning (Klabbers, 2009; Lukosch & Comes, 2019; Moizer et al., 2009; Smale et al., 2016).

The existing literature has already established lean simulation games as effective learning tools for lean construction. Currently, there is a growing body of literature focusing on lean simulation games in the construction industry, and this is expected to increase and evolve further in the coming years (Forbes et al., 2018; Nofera et al., 2015; Rybkowski et al., 2021). There are similar studies on game-based learning in the areas of manufacturing, management, education, and healthcare, etc., and this body of knowledge has already been investigated in reviews (Abdul Jabbar & Felicia, 2015; Badurdeen, Marksberry, Hall, & Gregory, 2010; de Freitas Avelar & Marques Carvalho, 2020; Martínez-Jurado & Moyano-Fuentes, 2017; Shou, Wang, & Wu, 2021b; Vlachopoulos & Makri, 2017). Despite significant increases in the dissemination and use of simulation games, there is a scarcity of comprehensive reviews of the development and application of simulation games in lean construction research. This gives rise to the need for a systematic review of the existing literature in the field of lean games and simulations specific to the construction industry. Not only will an extensive review help academicians improve their pedagogical approach to better understanding lean concepts and principles, but it will also create a map of the existing ecosystem of lean construction simulation games, so that educators, researchers, and simulations developers can avoid ‘reinventing the wheel’ where simulations currently exist and instead focus their efforts on developing new games where identifiable knowledge gaps can be identified. Such a map can also help existing and emerging simulation game researchers identify appropriate like-minded collaborators who can help synergize their efforts. In other words, a rigorous snapshot of the existing state of simulation games can facilitate the acceleration of research and development in the area of lean simulation games.

To this end, the purpose of this research is to provide to those engaged in the development and application of lean simulation games for the construction industry a comprehensive systematic overview and assessment of peer-reviewed, simulation-based lean construction research.

Research methods

Systematic reviews are gaining interest in a wide variety of fields with the primary purpose to plan, identify and evaluate studies to extract data trends from literature (Tranfield, Denyer, & Smart, 2003). Systematic reviews are an effective way to synthesize literature with rigour, transparency, and minimum bias to ensure future replicability (Innella, Arashpour, & Bai, 2019; Mallett, Hagen-Zanker, Slater, & Duvendack, 2012).

For this study, a search strategy was developed to collect relevant literature from the databases finalized by the authors. The data was screened with the help of inclusion and exclusion criteria defined during development of the search strategy. After screening, the final set of articles was evaluated to arrive at the results reported in this paper.

Search strategy

A search strategy was drawn, and this was used for the search process carried out in the on-line databases selected by the authors. The search strategy included identifying peer-reviewed articles that arose using relevant keywords defined by the authors of this article, and then screening these articles using inclusion and exclusion criteria to identify relevant literature from the databases. We applied our search process to the following databases: ASCE, EBSCO, Emerald, Science Direct, and Taylor and Francis. Conferences were included in this study (Catal & Diri, 2009; Erick & Smith, 2011; Jorgensen & Shepperd, 2007; Kugley et al., 2017) because they can serve as a prominent platform in which lean researchers, academicians, and lean enthusiasts in the construction industry around the globe share their research every year. For example, the International Group for Lean Construction (IGLC) conferences are an important and credible gathering of the lean community across the world to showcase advancements in the area of lean construction. The first annual conference was held in Espoo, Finland in 1993. The 30th conference was held in Edmonton, Canada in 2022. The papers in this conference go through a rigorous double-blind peer review process and the influence of this conference has increased over recent years. In a similar vein, the Lean Construction Journal is a prominent journal published by the Lean Construction Institute in which key researchers and practitioners in the area of lean construction have been publishing over the years. For these reasons, IGLC conference proceedings and LCJ were searched separately.

Step 1: paper identification

The keywords used for paper identification were Lean, Games, Construction, and Simulation. The search string defined initially for the search purpose was ‘Lean AND Simulation AND Game AND Construction’. However, each database had its own advanced search interface which had entirely different functional behaviours. Journals such as LCJ had limitations with respect to using advanced search functions. Therefore, relevant papers were identified by abstract and full text screening. We designed a specific search strategy while keeping in mind the search string. For example, Emerald Database offered an option for searching parameters such as Title, Abstract, Author, and DOI, whereas in the ASCE database, searches were limited to Title and Author. For databases such as Emerald and Taylor & Francis, keeping in mind the search strings, various combinations of the search words were explored during the initial search. Further, the results from these search strings were sorted by ‘relevance’. The EBSCO Database permitted searches using only three keywords at a time, but the string we defined for our search process held four keywords. Therefore, we maintained the same keywords and the search string was modified for each database to ensure that all papers relevant to this study have been identified. The initial search process generated a total of 13,781 + papers. All these papers were stored in separate folders with respect to the database for the systematic analysis. Some databases such as Science Direct presented an extensive number of search results, prompting us to take advantage of a function provided by the database, where relevance could be used to identify the papers aligned with the focus of this systematic review.

Step 2: screening

A two-step process was followed for screening the publications, namely, abstract screening and full text screening. In abstract screening, abstracts were reviewed from the perspective of their focus on lean simulation games for the construction industry. The review process was performed to ensure that the papers that were most relevant to the scope and objective of this review were selected. Further, the papers found relevant in the abstract screening were again subjected to full text screening. These papers were thoroughly read by a research member of our team, and in cases of uncertainty, a paper was referred to another member of the team. The full text screening ensured that all papers selected after screening were focused on the design and development of participatory, lean simulation games for the construction industry and not on computer-based games that had a different purpose. During the search process, there was a duplication in the papers identified because the same article could be present in multiple databases. All duplications were removed during the full text screening and the final papers were compiled into a single folder. At the end of the screening process after the search, abstract screening, and full text screening, 52 papers were found relevant for this particular study. Of these, 15 papers were from databases, three papers were from LCJ and 34 papers were from IGLC conference proceedings (Figure 1).

Figure 1. Funnel diagram showing flow chart of the systematic review process.

Selection criteria

The following inclusion and exclusion criteria were used for the selection of publications.

1. Studies published between 1990 and 2021 were included since lean construction simulation games entered lean research and education in the mid-1990s;

2. Literature published in English was considered for this review; and

3. Only peer-reviewed journal papers, conference papers, book chapters, and case studies were considered for inclusion.

Our exclusion criteria were as follows.

1. Publications written in languages other than English were excluded.

2. Publications that discussed the application and design/development of lean games and simulations in fields other than the construction industry were not considered.

3. Abstracts with no clear focus on lean games and simulation were eliminated.

4. Non-participatory simulations such as discrete event simulation and Monte Carlo simulations were considered of a different nature and were excluded from this review; and

5. Publications that reported games and simulations carried out using computer simulations and software were excluded from the analysis.

Step 3: included papers

A total of 52 papers were harvested in this systematic review of lean simulation games for the construction industry. Once relevant papers were identified, they were subjected to content analysis and a spreadsheet was developed to extract and synthesize the information from the selected papers. Information extracted from articles and inventoried on a spreadsheet included: name of database, name of the journal or conference proceeding, title of the paper, author(s), year of publication, countries of author(s), and name of simulation, etc.

Results and analysis

Distribution of papers included within the period (1990–2021)

Collective efforts to bring lean philosophy to the construction industry appear to have gained momentum in the mid-to-late 1990s with the establishment of two prominent institutions – the IGLC and LCI – founded in 1993 and 1997, respectively.

The foremost paper in the database was by Tommelein, Riley, and Howell (1999); the paper presents the development and testing of the Parade Game which demonstrates the negative impact of variability on workflow performance by trade partners. Figure 2 illustrates that few papers were published about lean simulation games (i.e. just six) before 2012. The maximum dip is evident from 2000–2004 where there were no contributions in this domain during five consecutive years.

Figure 2. Number of papers published per year within the review period; database distribution of total papers.

The highest number of relevant papers published annually was still no more than two before 2012. Those papers largely concentrated on the development and testing of a few important simulation games such as Parade of Trades, the Lego Airplane Game, LEAPCON, and the Apartment Construction Simulation Game. The slow start could be attributed to the then-ongoing discourse about the relevance of applying lean principles to the construction industry. Since 2012, the number of academic papers on this topic has increased steadily. The increase in the number of papers from 2012 – with an average of four to five per year – may be in part due to a rising world-wide acceptance of the new lean paradigm. Around that time, there also seems to have been a growing realization that an understanding of lean can be imparted to practitioners and university students through an effective hands–on mechanism in the form of simulation games.

Although there was only one relevant paper published in 2013, an upward trend in subsequent years is apparent; the highest number of papers published on simulations games rose to seven in 2014 and eight in 2021. It is likely that academicians and practitioners started to observe that simulation games offer an effective way to teach lean principles and bridge the gap between conceptual knowledge and application on actual projects. The rising rate of publications over time is one potential indicator of mounting interest in simulation games and their ability to impart practical lean skills, as well as to increase participant willingness to adopt a collaborative, lean mindset. In total, there were 96 lean simulation games described in 52 papers that were published within the review period (1990–2021).

Classification of papers included by database wise distribution

In this section, the distribution of papers across different publishers/ databases is analysed. The 52 papers deemed most relevant were drawn from the following six publishers/databases: ASCE, EBSCO, Science Direct, IGLC, LCJ, and Emerald as shown in the pie chart in Figure 2. The maximum number of papers came from IGLC (65%) followed by ASCE (19%). The remaining 16% of papers were drawn from EBSCO, Science Direct, LCJ, and Emerald. The distribution of the database can further be mapped over the number of papers published per year. It was noted that the IGLC has contributed at least one paper every year – with the exception of 1999. IGLC has also been a significant contributor and has done so consistently since 2012. Papers were published by ASCE over the course of five consecutive years, from 2014 to 2018.

Classification of papers included by country of origin

Earlier systematic reviews in the area of construction management focused on distributions of papers by country, (co)authors, or the institutions associated with the study (Zhou, Irizarry, & Li, 2013). In this study, our analyses of papers in terms of country of origin were related to the institution to which the author was affiliated. Some papers were classified as ‘others’ where (co)authors from different countries collaborated and conducted the research. Fourteen countries spread across five continents were covered as shown in Table 1. The distribution of the papers is as follows: 21 papers from the United States, three papers each from India, Israel, and Germany, two papers from Sweden, and one paper each from Switzerland, Brazil, Denmark, Finland, Italy, Lebanon, Peru, United Kingdom and Australia. The maximum number of papers (approximately 40% of the total) originated in the United States. Papers from developed countries (United States, Germany, Sweden, Switzerland, Denmark, Finland, Italy, Israel, United Kingdom, and Australia) comprised three-fifth of the papers and there were only a few from developing countries (India, Brazil, Lebanon, and Peru). It is possible there are more papers from developed countries for the following reasons:

1. Although not always the case, more construction activities tend to take place in developed than in developing nations;

2. Lean simulations and games are popular as a pedagogical approach in developed nations; and

3. There is greater awareness of lean practices in the construction industry in developed nations as lean philosophy is included in the course curriculum of a number of construction management programmes in countries such as the US.

Table 1. The number of relevant papers by country/region

Country/Region	Number of papers
United States of America	21
Others	11
Israel	3
India	3
Germany	3
Sweden	2
Switzerland	1
Brazil	1
Denmark	1
Finland	1
Italy	1
Lebanon	1
Peru	1
United Kingdom	1
Australia	1
Total	52

Further analyses indicate that of the 11 papers falling under the ‘others’ category, 10 represented collaborative efforts among researchers in both developed and developing countries and only one paper was written by authors of developed countries. Collaborations between researchers from developing and developed nations points to an increasing interest among the former to learn from the latter, and to adopt and implement simulation games as a learning tool.

Classification of papers included by publication type and publication name

Based on the search and screening process, the following types of peer-reviewed publications were included as part of our analyses: Journal papers (25%) from six journals and conference papers (75%) from five conferences. Table 2 shows the publications and the numbers of papers corresponding to each publication. There were 34 papers from the International Group of Lean Construction (IGLC) conference, which comprised 65% of the total. This indicates the prominence or significance of the IGLC conference in the area of lean simulation games. There were four more conference papers from other conferences in addition to IGLC, bringing the total to 38.

Table 2. Publication names and the number of corresponding papers.

Publication name	Number of papers
International Group for Lean Construction (IGLC)	34
Journal of Professional Issues in Engineering Education and Practice	5
Lean Construction Journal	3
Journal of Construction Engineering and Management	2
Journal of Management in Engineering	1
European Journal of Engineering Education	1
Journal of Engineering, Construction and Architectural Management	1
Sustainability	1
Conference of Learning Factory	1
Creative Construction Conference	1
Construction Research Congress	1
ICCREM: Smart Construction and Mngt in the Context of New Technology	1
Total	52

After the IGLC, the next largest number of papers came from the ASCE database: 10 papers, adding another 19% to the total. Papers and their quantities (inserted in parentheses) from the ASCE database were from publications such as the Journal of Professional Issues in Engineering Education and Practices (2), the Journal of Construction Engineering and Management (5), the Journal of Management in Engineering (1), and conference papers from Construction Research Congress (1), and International Conference on Construction and Real Estate Management (1). Other contributing journals were Lean Construction Journal (3), European Journal of Engineering Education (1), Engineering Construction and Architectural Management (1).

The Social Network Analysis (SNA) map shown in Figure 3 was designed in the form of a spiral increasing inward to illustrate the growth in collaboration among authors across different databases. The size of each node represents the number of papers written by a unique author. For example, author Z. K. Rybkowski resides at the centre of the spiral with the largest node as this researcher authored or co-authored 11 articles from 52 research studies reviewed in this study – the largest number of research papers related to lean simulation games. Authors with fewer papers are located farther from the centre of the spiral. The lines that connect the nodes represent a direct collaboration between (co)authors.

Figure 3. Social Network Analysis (SNA) Map showing unique authors and their level of collaborations across different databases.

The SNA map shows that the number of lines and size of nodes decrease as one moves farther away from the centre. This means that the authors located at the centre are engaged in extensive collaboration and are involved in writing a greater number of papers on lean simulation games. The smaller nodes with no lines projecting outward from them represent papers with a single author. For example, the following authors, H. Lidelow, J. Von Heyl, O. Seppanen, S. Lindhard, and X. Briosoa have each written single-author papers.

The inferences drawn from this map are as follows. The SNA map shows that, in addition to Z. K. Rybkowski, a number of other researchers are active in developing and publishing lean simulation games. For example, T. da C. L Alves, G. A. Howell, C.C.Y. Tsao, V. A. Gonzalez, and R. Sacks have also written a relatively large number of articles on the topic. Publication activity of each author is indicated by the diameter of their node and collaborations are indicated by the number of lines connected to other nodes. There is a dense network of collaboration observed with a number of lines projecting outward from the core of SNA map with larger nodes, indicating vibrant dialogue and collaborative activity among a few sets of authors.

There are many authors such as X. Briosoa, E. Raucha, M. Musa, etc. who are at the peripheral level of this SNA map. This indicates that these authors have not yet collaborated with other lean researchers on this topic and may still be in their early stages of research pertaining to lean simulation games. To move this body of knowledge forward, it is important that the exchange of ideas be enhanced through collaboration between the researchers at the centre and those at the periphery of the spiral. Such types of collaborations typically lead to a synergistic flattening of learning curves and greater rates of effective innovation.

The colour of different lines in the SNA Map indicate databases / publication types used by authors for showcasing their work in the area of lean games and simulations. For instance, A. Lahouti, T. S. Abdelhamid, and W. Nofera are connected with red lines, meaning they are co-authors of an article for the LCI-housed journal, LCJ. From this map, it can be inferred that the authors who consistently collaborate and publish in this field are using the annual conferences of IGLC to present their work and synergize their efforts. Interestingly, emerging authors shown at the periphery of the SNA map are also using the IGLC to present their ideas and forgo collaboration with prominent authors. ASCE was the next prominent publication that is being used by researchers in this field to publish their work. However, the number of authors and extent of collaborations in ASCE were considerably smaller than those in IGLC.

World map showing location of unique authors

Figure 4 maps the number of unique authors in various countries around the world. Each (co)author from a particular paper was classified as unique, based on his or her location. 52 papers were analysed for this study and were written by a total of 124 unique authors affiliated with 23 countries. Of these, 114 authors were faculty and students affiliated with 38 academic and research institutions and universities while 10 authors were from nine companies and lean consultancies. The maximum number of unique authors who collaborated on a single paper was seven. There were two papers from IGLC falling under this category: ‘Accelerating the Last Planner System (LPS) uptake using virtual reality and serious games: A socio-technical conceptual framework’ by Liu et al. (2020) and ‘Virtual Parade Game for lean teaching and learning in students from Brazil and Chile’ by Biotto et al. (2021).

Figure 4. World map showing location and number of unique authors.

It can be seen that the majority of the (co)authors by numbers were from the US (39), followed by India (11), Germany (10), Chile (7), Brazil (6), Italy (5), Lebanon (5), Hong Kong (5), and New Zealand (5). The international nature of the group indicates that this body of knowledge on lean simulations and games has now attained global presence and has become a part of lean concept training/ teaching at varying levels of understanding and application. However, (co)authors from the developing economies are not well represented on this world map, which shows the untapped potential of these countries.

The regional distribution of the (co)authors with reference to this particular map also indicates that North and South America (US, Canada, Mexico, Columbia, Peru, Brazil, and Chile) accounted for the highest number of (co)authors (i.e. 56). This was followed by European Union (EU) countries such as Germany, Finland, Sweden, Netherlands, United Kingdom, Denmark, Georgia, Spain, Italy, and Switzerland with 35 authors. Such a pattern can be attributed to concentrated efforts being made both in academia and in the construction industry to adopt lean concepts. The increasing presence of the Lean Construction Institute (LCI) and The International Group for Lean Construction (IGLC) in North and South America and the European Union could be another reason for their higher presence in publications. The same trend was seen in other economies, and a slight gain in lean momentum was observed in India, likely due to the active presence of institutes such as the Institute for Lean Construction Excellence (ILCE).

Classification of papers across different categories

A careful study of the 52 papers chosen for this review showed predominantly three focal areas of these papers – conceptual review, application / analysis of an existing game, and development and testing of a game (a new game or a variant of any existing game).

The first category, ‘conceptual review’, was defined as any study that focused on overviews of various existing lean games in the domain of construction. Examples include papers that analysed lean games investigating a specific area of lean such as waste or productivity, or providing a broader overview of game or games without an in-depth analysis. The second category, ‘application/ analysis of an existing game’ included papers that discussed application and analysis of an existing game in a different context such as country, type of participants (i.e. industry professionals versus students), and reports of the efficacy of the game for the entirely new setting. The third category, ‘development and testing of a game’, included papers that focused on the development and testing of a new or variant simulation game, with detailed accounts of the research methodology, trial run and debriefing.

Results of our detailed analysis of the 52 papers with respect to the three categories are presented in Figure 5.

Figure 5. Division of games across three categories and publication names.

Of the 52 papers, a majority – 34 papers (65% of the total) – could be classified as development and testing of a game, 13 papers (25%) could be considered as a conceptual review, and five papers (10%) were included in the category of application / analysis of an existing game.

The largest number of papers focusing on development and testing of a game is an indication of the vibrant, ever-growing body of knowledge related to the development of new games and variants of existing games with diverse and interesting topics such as kaizen, push–pull, waste, or delta (improvement). In particular, the development of variants of an existing game demonstrates a type of continuous improvement within a body of work that is evolving to suit different settings. The 13 papers categorized under ‘conceptual review’ provide an overview of game development focusing on specific areas at a higher level.

There were only five papers in application / analysis of an existing game category. These papers may represent an intent to create generalizability and applicability to different stakeholders within the construction industry. The large difference between the number of papers classified as development and testing of a game and application / analysis of an existing game is also evident. It shows that while there is a substantial influx of new/ variant games in the industry, there is also a need to adopt these games for application and to report on the efficacy of the games when facilitated in actual settings.

From among the databases, the International Group of Lean Construction (IGLC) supplied the largest number of papers on simulation games and was identified as one of the prominent platforms to report development and testing of novel games and dissemination within the lean research community. Of the IGLC-published papers that form part of the analyses, 24 focused on the development and testing of a game, eight on conceptual review and two on application of an existing game. This suggests that the IGLC has created a thick and closed-knit global community for dissemination of lean construction simulation games. In terms of paper counts, the IGLC was followed by the Journal of Construction Engineering and Management, which published four papers on the development and testing of new games (Figure 5).

Classification of simulation games by rating on level of discussion

During our thorough review of 52 papers, 96 games were identified. These games were rated based on the detail provided in the papers relevant to a specific game. There is a possibility that some games in the list were presenting variants (slight or considerable) of other games on the list. Some simulation games could also be identical to other games and primarily represented a name change of an existing game (i.e. the Red-Green Game is methodologically similar to the Maroon-White Game and the Red-Black Game) (Zofia K. Rybkowski et al., 2018). Simulation games with such similarities could be combined for analysis in future research.

By way of example, M. Munankami's Target Value Design (TVD) Simulation/Tower Game/TVD Marshmallow (Rybkowski & Forbes, 2016) introduced a TVD estimating component into the Marshmallow Design Challenge game by Peter Skillman (Skillman, 2006; Wujec, 2015). Two virtual variants, Marshmallow Tower TVD simulation-Online Version (Jacob et al., 2021) and TVDfDFAB Game (Ng & Hall, 2021), used slightly different tactics from the in-person version of the game. While both the games, Marshmallow Tower TVD Simulation-Online Version and TVDfDFAB Game, used Google Slides® and Google Sheets® for facilitation, the former simulation game assigns to players the roles of owner, designer, and contractor, focusing on the construction of a tower, while the latter assigns the roles of a restaurant owner, artistic chef, recipe chef, and executive chef, focusing on developing a plate of salad using ingredients such as carrots, cucumbers, tomatoes and eggs. In addition, the TVDfDFAB game intends to teach and promote the use of digital fabrication (DFAB) in TVD during design.

Another example of a simulation with multiple variants is the Parade of Trades, an original simulation game, developed by Greg Howell and Iris Tommelein (Tommelein et al., 1999). The game shows how workflow variability affects construction trades and their successors’ performance. Its variant, ‘Parade Plus’ (Mitropoulos, Alves, & Walsh, 2014), shows how the ‘Parade of Trades’ simulation has been enhanced by allocating a cost to represent the expense of planning for various levels of variability. It was difficult to determine if these simulation games are comparable or different and were therefore treated individually in our analyses.

Each simulation listed in Figure 6 was analysed in terms of the levels of discussion in each paper. Three levels of discussion were identified, viz., slightly discussed, moderately discussed, and significantly discussed:

1. Slightly discussed category – The simulation game is discussed briefly in the text of papers, such as simply mentioning the name or/and objective of the simulation.

2. Moderately discussed category – The simulation game is discussed concisely with a few details in short paragraphs about the structure of the game and its various classifications.

3. Significantly discussed category – The simulation game is discussed in detail in terms of its development and testing, with full details about the structure of game (e.g. rules, resources required, number and type of actors/players, various classifications such as delivery formats, learning outcomes, and interaction style, etc.)

Figure 6. Scattered map showing simulation games with analyses based on level of discussion.

The simulation games addressed in the study were plotted against the categories listed above based on the frequency with which their names were mentioned. From Figure 6, it can be inferred that a majority of the simulation games were slightly discussed in the 52 papers. Of the 96 simulation games, 75 games (78%) fell under the slightly discussed category. In the moderately and significantly discussed categories there were 21 (22%) and 34 (35%) simulation games, respectively. In fact, only 19 (20%) simulation games were discussed more than once in all categories. A few simulation games were discussed once in each category, 30 simulation games were discussed once in the slightly discussed category, 16 simulation games in the moderately discussed category, 20 in the significantly discussed category. This indicates that more research is needed to examine/ analyse simulation games that are already covered in slightly discussed category. Conversely, games such as the Parade of Trades (25), LEAPCON Simulation (19), Lego® Airplane Game (17), Villego® Last Planner® System Simulation (13), Silent Squares/ Broken Squares (10) seem to be the most popular games in the lean community with varying levels of discussions.

Limitations of the study

It must be acknowledged that a main limitation of this study is that our analyses of lean simulation games was based only on information presented in a particular paper. Because we could not collect firsthand information from the simulation creators to verify details about similarities or differences between simulations, we were unable to make a judgment call about whether or not certain simulations should be grouped together. Therefore, the list of simulation games summarized and shown in Figure 6 considers each simulation as a distinct entity. Further studies need to be undertaken by contacting the creators of these games and collecting detailed information such as the simulation game’s aim, manner of role-play, materials needed, number of rounds, and format in which the game is played, etc. This information can be used to ascertain similarities and thereby promote better grouping. Additional information directly from the author / developer of the games and simulations can result in identification of additional opportunities for analysis and game development.

Another limitation of this systematic review is that only studies published in the English language were included and this could have eliminated relevant publications in other languages, notably Chinese and French. Also, while there are numerous conferences, many proceedings are not available to outsiders; therefore the scope of this paper was necessarily limited to the peer-reviewed conference proceedings that are available on-line and the type of lean simulation games analysed fall within the defined scope of this paper.

Conclusion

Lean construction has been making inroads in architecture, engineering and construction (AEC) sectors and its adoption at a global level is on the rise. More efforts are required to integrate lean philosophy into construction projects and this demands extensive training. The potential of lean simulation games to offer participants an intuitive understanding of lean concepts seems unparalleled. The effectiveness of simulation games appears to be increasingly recognized by lean champions, industry professionals and academicians, as demonstrated by their growing use. It appears the AEC industry is approaching a sustained momentum to use lean simulation games for enhanced learning. This systematic review is a first attempt to analyse the body of knowledge pertaining to lean games and simulations from diverse perspectives such as year of publication, database, publication type and name, social network analysis of authors and collaboration, author location, and level of discussion. In total, 52 manuscripts were analysed dating between 1990 and 2021. This analysis provides valuable insights into the evolution of lean simulation games as they have evolved in the global landscape. A study of distribution of papers over time, during the review period of 1990–2021, showed an increase in numbers of papers since 2012, which indicates a growing interest in the lean community to use lean games and simulations as part of professional training and academic coursework. Over the years, the annual conferences of IGLC have become eminent platforms for idea-sharing, presentations, and physical demonstrations of new lean games and simulations. Currently, there are a few prominent authors who collaborate and consistently publish in the domain of lean games and simulations. Interestingly, new researchers who are beginning to publish in the area of lean simulation games appear to be forging collaborations with researchers more experienced in the field. It is likely that, in the near future, these enhanced collaborations will result in transformations of existing lean simulation games across geographies as well as lead to the development of new simulation games. Perhaps because of the presence of highly active institutions such as LCI and IGLC, as well as the incorporation of lean philosophy into an increasingly centralized topic within academic curricula, more papers originated from authors in North and South America and the European Union than from those in developing countries. However, other economies are emerging, and the growth trend of simulation games is bound to increase as lean philosophy gains momentum in other parts of the world as well. Although it is exciting to note that a majority of papers have focused on the development and testing of simulation games – an indication of continued innovation and creation of new lean simulation games – there is also a need for greater emphasis on application and analysis of existing games and simulations. Correcting this imbalance can lead to a more holistic understanding of lean philosophy and its applicability to the AEC industry.

We recommend that future research investigates variants of lean simulation games and identifies distinguishing features of each variant. Additionally, a comparative study between lean simulation games that emerged from and are being applied to the manufacturing sector and the AEC sector needs to be performed. Such a study can provide synergistic opportunities for inter-sectoral learning and accelerated development of new games and simulations useful to both sectors.

Disclosure statement

No potential conflict of interest was reported by the author(s).