Social vulnerability and population loss in Puerto Rico after Hurricane Maria

Communities in Puerto Rico saw their populations shrink after Hurricane Maria in 2017. Of the archipelago's 884 populated census tracts, 613 tracts (69.3%) experienced a net population loss with an average loss of 161 people. To understand the relationship between social vulnerability and post-disaster population loss, informed by theories of environmental migration, I compare a measure of social vulnerability in Puerto Rico to population change in each tract. This study also provides an opportunity to evaluate the validity of the social vulnerability index (SVI) in Puerto Rico. Through six spatial regression models, I find that the current 15-variable SVI significantly predicts greater population loss for more vulnerable areas in Puerto Rico, in which the most vulnerable tracts lost 81 more people than tracts at the median. However, a revised 10-variable SVI-created after factor analysis by removing variables for mobile homes, group quarters, multi-unit dwellings, minority status, and limited English proficiency-produces an even larger effect size when predicting population loss, in which the most vulnerable tracts lost about 175 more people than the least vulnerable. Results suggest that a 10-variable SVI may have higher construct validity for the context of Puerto Rico and could become a foundation for a measure that better reflects local experiences with disaster. This is the first study to test the relationship between a social vulnerability index and post-disaster population change in Puerto Rico. These findings highlight the need for further investigation of the link between social vulnerability and post-disaster migration and underscore the importance of context-specific measures of social vulnerability.