Digging for quality and quantity: A systematic review of economic valuation studies of ecosystem services in Peru

This study focuses on Peru, a South American country renowned for being home to 10% of global biodiversity. However, Peru only contributed two valuation studies to the Ecosystem Services Valuation Database (ESVD), the largest database that contains over 1300 valuation studies associated with more than 9400 data values as of 2022. We carried out a systematic review of environmental economic valuation studies in Peru, identifying 174 primary valuation studies. 50% of the identified studies were rigorously analyzed and registered in an open-access database with 220 data values. To critically assess the academic rigor, a typology of “low-quality studies” was adopted, finding that 69% of Peruvian valuation studies provided minimal to no contributions to the valuation of ecosystem services in Peru. Those studies deviated from established best practices in environmental economics, notably in their inadequate application of valuation methodologies, flawed sampling techniques, and insufficient consideration of the time value of money. In more than 35% of the data values, the year when the value observation was estimated was not identified. Financial constraints on conducting primary studies and the poor specialization of economists (and non-economists) in valuation methods are the main reasons for the prevalence of low-quality studies. Despite its methodological limitations, this study can be a starting point for developing environmental economic valuation in Peru.