Expert adoption of composite indices: a randomized experiment on migrant resettlement decisions in Bangladesh

In settings where complex social decisions are made, information is often aggregated into indices to facilitate decision making. The value added of such composite indices depends, inter alia, on the extent to which decision makers trust and make use of them. This paper presents a randomized experiment on the use of an index designed to inform migrant resettlement decisions, using 410 graduate students in Bangladesh as respondents. Respondents were randomly assigned to control and treatment conditions. In the control group, respondents faced a discrete choice experiment where they were asked to allocate 1000 migrants between two locations described by five attributes (availability of cropland, distance to hospital, distance to school, poverty incidence, frequency of floods, droughts and cyclones). In the treatment group, respondents also had access to the migrant resettlement index for the two locations. Results show that the resettlement index is used by the respondents, and mechanism analyses suggest this is due to perceptions of improved benefits to costs from using the index to make decisions. Results from the control group also suggest that past adverse environmental events are particularly important for resettlement decisions, but less so for respondents who grew up in areas where such events were frequent.