A PORTABLE DATALOGGER TO EVALUATE RECALL-BASED TIME-USE MEASURES

Self-completed recall &aries have become a common tool in epidemiology and exposure assessment to determine the location and/or activities o f subjects during study periods. Unfortunately, little effort has been made to determine the accuracy of such an approach for providing info rmation without significant bias. It is usually assumed that subjects are truthful and complete in their recall. An electronic datalogger ha s been designed to allow subjects to record location changes as they o ccur in real time. Subjects carried the datalogger for 3-5 days and co mpleted recall diaries at the end of each day. The concordance between the two records was found to be relatively good for the most commonly visited locations, e.g., bed/bath, workplace, etc. Poorer agreement w as found for locations of short or infrequent visits, e.g., cellar or vehicle. The merits and shortcomings of the datalogger approach are di scussed. While having external validation for recall diary records is clearly necessary, reliance on subject input to the datalogger present s its own problems related to subject compliance. Electronic approache s which do not require active subject input are recommended to aid in the evaluation of recall diaries.