Finally, contrasting differences of baseline and follow-up analyses are often observed and may be due to a patient’s ability to recall recent versus past events. In the COGA study, subjects were assessed at baseline regarding their current and lifetime characteristics. At the follow-up interview, they were again assessed for both their current (including most recent events during the follow-up period) period as well as lifetime characteristics. Thus, individuals might recall the more recent events more completely and accurately than more remote events. This potential recall difference underscores the necessity for prospective studies which might provide more accurate data than cross-sectional data collection designs to reduce individual recall bias.
