Optimal recall length in survey design.

Self-reported data collected via surveys are a key input into a wide range of research conducted by economists. It is well known that such data are subject to measurement error that arises when respondents are asked to recall past utilisation. Survey designers must determine the length of the recall period and face a trade-off as increasing the recall period provides more information, but increases the likelihood of recall error. A statistical framework is used to explore this trade-off. Finally we illustrate how optimal recall periods can be estimated using hospital use data from Sweden's Survey of Living Conditions.