Does mitigation save? Reviewing cost-benefit analyses of disaster risk reduction

The benefit-cost-ratio (BCR), used in cost-benefit analysis (CBA), is an indicator that attempts to summarize the overall value for money of a project. Disaster costs continue to rise and the demand has increased to demonstrate the economic benefit of disaster risk reduction (DRR) to policy makers. This study compiles and compares original CBA case studies reporting DRR BCRs, without restrictions as to hazard type, location, scale, or other parameters. Many results were identified supporting the economic effectiveness of DRR, however, key limitations were identified, including a lack of: sensitivity analyses, meta-analyses which critique the literature, consideration of climate change, evaluation of the duration of benefits, broader consideration of the process of vulnerability, and potential disbenefits of DRR measures. The studies demonstrate the importance of context for each BCR result. Recommendations are made regarding minimum criteria to consider when conducting DRR CBAs.