The Japan International Cooperation Agency (JICA) introduced guidelines for environmental and social considerations in April 2004. The guidelines could lead to an improvement in the quality of environmental and social consideration reports. The main reason for this may be the inclusion of alternatives analysis and public involvement. This study aimed to quantitatively verify the effectiveness of alternatives analysis and public involvement, and to propose concrete methods for improving the quality of reports based on the analytic result. The Lee-Colley review package was used to review the quality of the samples of 120 reports dating from 2001 to 2012. A path analysis with structural equation modeling was used to obtain a causal model. The rating scales from A to F (ordinal scales) were converted to rank scores and analyzed using a statistical technique. This paper acknowledges the effectiveness of alternatives analysis, public involvement, and the number of criteria for improving the quality of the reports. The effectiveness of those variables may be verified by the causal model. As a result of statistical analysis, the paper points out the effectiveness of alternatives analysis with a wide range of criteria and public involvement. Further research is needed to improve the causal model by attaining new knowledge, to find out what are the concrete benefits of public involvement to the quality of the reports, to verify the most suitable number of alternatives and criteria for alternatives analysis, and to prepare technical guidelines for the use of the quantitative technique of alternatives analysis in case studies.
Keywords: environmental and social considerations, alternatives analysis, public involvement, The Lee-Colley review package, path analysis