## 3 Review Protocol and Implementation
### Initial Screening
#### 3.2.2 Bibliometric Analyses and Paper Clustering  
Bibliometric analyses of these remaining 93 papers comprise at this stage statistics about  
* Documents by author (Figure 5a)
* Documents by country (Figure 5b)
* Documents by subject (Figure 6a)
* Documents by type (Figure 6b)  
The bibliometric analysis shows in Figure 5b that most of the relevant documents were published by American researchers (25). Also, the United Kingdom (11), Brazil (10), Israel (10) and Germany (9) appear to be very active in the field of joint BIM-LPS applications. Figure 5: Documents by author (**a**); documents by country (**b**). \begin{table}
\begin{tabular}{c c c} \hline \hline
**Inclusion** & **Exclusion** \\ \hline \(\bullet\) & Written in English & \(\bullet\) & Written in a language other than English \\ \(\bullet\) & Peer-reviewed journal/conference papers & \(\bullet\) & Not peer-reviewed; contribution constitutes book, book section, technical report and similar \\ \(\bullet\) & Related to the construction phase & \(\bullet\) & Related only to the design phase \\ \(\bullet\) & Deals with at least one element of each concept & \(\bullet\) & Deals only with one of the concepts (BIM **(BIM AND LPS)** \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Inclusion and exclusion criteria. Figure 5a presents the document distribution by authors. Here, [PERSON] is the author of the most publications. This underlines his significance in this field of research, who is already playing an important role in this review as the first author of the original BIM-Lean interaction matrix. On the other hand, Figure 6 shows the document distribution by subject (a) and type (b). Especially the type distribution is noticeable as it reveals that the majority of publications are presented at research conferences. This could be an indication that many observations and considerations in this research area have not yet been consolidated and that, accordingly, there are not yet enough reliable findings for extensive publication in journals. In addition to that, science mapping visualizations were conducted with _VOSViewer_ software (Figure 7). _VOSViewer_ is a freely usable software system based on text-mining algorithms and network clustering techniques which has been developed by [PERSON] and [PERSON] [46]. It allows for distance-based cluster visualization of bibliometric networks [47], where the size of the nodes in our settings renders absolute occurrences of analyzed terms in title and abstract fields of the literature sample. The distance between the nodes, on the other hand, visualizes how much related to each other the terms are, meaning how often they occur in the same paper. The clustering in different colors is done automatically by the software. However, the user can decide how many clusters the system should generate and by doing so, fine-tune clustering results. The detailed settings that we chose are summarized in Table 4.  
The rationale for this clustering approach was to identify the most relevant macro topics that BIM-LPS co-applications in scientific studies deal with. The results of the cluster visualization are shown in Figure 7.  
Figure 7 shows the most occurring terms in the considered literature sample of 93 papers, which have been grouped into three different clusters by the _VOSViewer_ clustering algorithm:  
1. The red cluster contains characteristic terms such as e.g., site, construction process, production, control, operation, worker, workflow, so that we grouped these terms to the cluster of production planning and control. 2. The green cluster contains characteristic terms such as e.g., information modeling, information technology, implementation, analysis, communication, so that we grouped these terms to the cluster of information systems and implementations. 3. The blue cluster contains characteristic terms such as e.g., coordination, team, project participant, project team, so that we grouped these terms into the cluster of collaboration.