## 5 Analysis of Results
### Scope of Results  
Publications on decision support methods related to civil engineering are more closely associated with environmental, sustainability or risk conscious engineers, or projects. It could also be possible that engineers working in the environmental/sustainability areas are more likely to have the results of their analyses published. This may be a combination of (a) the engineer's decision to write a paper on their work and submit to a journal or conference or (b) more interest from journals or conferences in accepting such papers, or (c) choice of keywords. The latter may be an unintended effect of being too specific with all keywords. For example, there are some civil engineering related papers that this author knows that were not identified in the bibliometric search. As the journals concerned were indexed in the databases, the author's choice of keywords or article title did not include sufficiently broad terms relating to engineering to trigger the search criteria above. Examples of these are an early paper on the application of ELECTRE III to choosing stations for renovation in the Paris Metro system [42]. While in the civil engineering (transport) domain, it was published in an Operations Research journal and was not picked up in the literature search. Another example is a paper on using AHP for selecting wastewater treatment options in the developing world [43] which, although published in a mainstream Civil Engineering journal, was not picked up in the broad search. While it uses the AHP method it does not mention multi-criteria or any variation of that phrase, using \"systems analysis technique\" and \"optimization\" instead. While researchers looking for information on a specific method or type of application, will search using very specific keywords, review studies tend to use keywords with a broader scope and may miss some papers that do not have some such \begin{table}
\begin{tabular}{c c c} \hline
**Rank** & **Keywords** & **Number of Articles** \\ \hline
1 & Decision making (or decision-making) & 62 \\
2 & Civil engineer & 46 \\
3 & Model & 42 \\
4 & Construction or (construction industry) & 36 \\
5 & Optimization & 35 \\
6 & System (or systems) & 32 \\
7 & Selection & 32 \\
8 & AHP (or Analytic Hierarchy Process) & 32 \\
9 & Management & 30 \\
10 & Water resources or (water management) & 30 \\
11 & Sustainable development & 24 \\
12 & Design & 22 \\
13 & Performance & 21 \\
14 & Framework & 16 \\
15 & Risk Assessment & 16 \\
16 & Engineering education & 14 \\
17 & Uncertainty analysis & 14 \\
18 & Climate change & 13 \\
19 & Criteria & 13 \\
20 & Environment & 12 \\
21 & Human resource management & 12 \\
22 & TOPSIS & 12 \\
23 & GIS & 11 \\
24 & Project management & 11 \\
25 & Safety engineering & 11 \\ \hline \end{tabular}
\end{table} 
Table 2: Top 25 keywords in articles. keywords. A mix of some very specific keywords together with some broad keywords indicating, e.g., the engineering discipline would have ensured these papers were selected. Of the various methods listed in the background section above, only two MCDA methods appear in the keyword list and these are the Analytic Hierarchy Process (AHP) [6] and TOPIS [7], suggesting these are the most frequently used methods worldwide. This is further supported by the top ten list of papers cited by the documents in the database, Table 3. Three documents in the top ten are by [PERSON], one describing the Analytic Hierarchy Process (AHP) method and the other two later papers describing its use in practice. The top ten also contains the paper by [PERSON] and [PERSON] describing the TOPSIS method. Additionally, two documents relating to outranking methods, i.e., the book by [PERSON] and a review paper by [PERSON] confirm that outranking methods [44] are widely known, if not as widely used as AHP. Three other documents in Table 3 relate to the use of fuzzy sets in MCDA.