Figure 3
A bar chart presents the number of papers by research method on the horizontal axis, with frequency on the vertical axis. Case study is the most frequently used method with 15 papers. Mathematical modelling follows with 13 papers. Conceptual papers account for 12 papers. Literature review includes 11 papers. Interview and survey methods account for 9 papers. Statistical analysis is the least used method with 3 papers.Number of papers per method