Appraising investments in Disaster Risk Reduction (DRR): A systematic literature review

Investments, including those allocated for Disaster Risk Reduction (DRR), need to be appraised before project implementation. Despite scholars' efforts to evaluate DRR investments over the years, a notable gap exists in the literature regarding systematic reviews focused on this topic. Therefore, this study aims to address this gap by conducting a systematic literature review of previous studies assessing the feasibility of DRR investments. The dataset for this review comprised 87 articles sourced from the Scopus database. The findings have been presented according to the research questions of the study, the methods used for appraisal of DRR investments, the types of costs and benefits considered, and the strengths and limitations identified by studies related to the appraisal techniques. Additionally, bibliographic data, the types of hazards considered for DRR investments, and the study contexts were identified. Notably, a significant portion of studies focused on the USA, with investments for flood mitigation representing the majority of investment appraisals. The findings highlighted that cost-benefit analysis was the predominant method used for evaluating DRR investments. Generally, cost estimation was straightforward, which included the initial investment and the maintenance expenses. However, discrepancies exist in the benefits considered by different researchers and the approaches used to quantify them. Based on these findings, the authors suggest future research directions and recommendations aimed at enhancing investment appraisals for DRR. • The study systematically synthesises research focusing on investment appraisal techniques used to evaluate DRR investments • DRR investments are evaluated using different categories of investment appraisal techniques, such as cost-benefit analysis and investment optimisation. • The costs of DRR investments primarily include investment and maintenance costs, with a limited number of studies focusing on other costs. • Studies have recognised various benefits for different hazards, with limited attention on indirect benefits and co-benefits of DRR • Future research directions and recommendations aimed at enhancing investment appraisals for DRR have been suggested