Understanding the Impacts of a Natural Disaster: Evidence from the 2004 Indian Ocean Tsunami

Measuring impacts of extreme events on population well-being is complicated if data are not representative of the pre-event at-risk population or a representative sample of the population is not followed post-event. The sources and nature of some important biases are documented using data from the Study of the Tsunami Aftermath and Recovery (STAR) which documents the evolution of population well-being before and after a major natural disaster, the 2004 Indian Ocean tsunami. The baseline, collected 10 months before the tsunami, is representative of the at-risk population. Respondents have been followed and re-interviewed multiple times in the fifteen years since the tsunami achieving high follow-up rates. We empirically document the importance of construct samples that represent the pre-event at-risk population, rather than an opportunistic sample of those in the vicinity of the event. Pre-event characteristics condition where and in what circumstances people live post-event. Post-event well-being is associated with post-event living conditions in the short-term, and that over time, the link weakens between short-term living arrangements and post-event well-being. Failure to follow-up all respondents, especially those who move away from the location of the event, yields biased estimates of impacts of the event.