Self-selection bias and cost-of-living estimates

Due to continued interest in geographic living-cost differentials, some researchers have used data from the ACCRA Cost of Living Index. This paper explores further the potential for using ACCRA data for cost-of-living research. In particular, it investigates the possibility of self-selection bias affecting OLS estimates using ACCRA data. The findings indicate that self-selection bias is a concern that researchers using ACCRA data should be aware of. Results using Heckman’s two-step procedure to estimate a cost-of-living model indicate promise for using ACCRA data to update and expand upon previous cost-of-living research. The author wishes to acknowledge Keith Ihlanfeldt and Cynthia Rogers for constructive comments on an earlier version of this paper presented at the 35th Meeting of the Southern Regional Science Association and also wishes to thank the two anonymous referees for their suggestions on improving the paper.