The current guidance for selection of recall periods recommends considering the design of the study, nature of the condition, patient\'s burden and ability to recall, and intent of the outcome measure. Empirical study of the accuracy of recall periods is recommended; however, there is not consensus on how to quantitatively evaluate the consistency of results from patient-reported outcome measures (PROMs) with different recall periods. We conducted a systematic review to describe quantitative methods for evaluating results obtained from PROMs with differing recall periods to lay the groundwork for establishing consensus.
We searched MEDLINE, Embase, Scopus, and American Psychological Association PsycINFO for studies where participants are given the same health-related measure (eg, quality of life, well-being, functioning, and pain) with differing recall periods.
A total of 7174 abstracts were screened. The 30 included studies reflected a wide range of domains, including pain, fatigue, and sexual behavior and function. The recall periods ranged from momentary to 6 months. The analytic approaches varied, including different methods for assessing relative agreement, absolute agreement, and for assessing combined relative and absolute agreement.
We found variability in how PROM recall periods were evaluated, suggesting an opportunity for greater consensus on methodological approach. As a starting point, we provide recommendations for which methods are preferred for which contexts.

Self-reported data on health care use is a key input in a range of studies. However, the length of recall period in self-reported health care questions varies between surveys, and this variation may affect the results of the studies. This study uses a large survey experiment to examine the role of the length of recall periods for the quality of self-reported hospitalization data by comparing registered with self-reported hospitalizations of respondents exposed to recall periods of one, three, six, or twelve months. Our findings have conflicting implications for survey design, as the preferred length of recall period depends on the objective of the analysis. For an aggregated measure of hospitalization, longer recall periods are preferred. For analysis oriented more to the micro-level, shorter recall periods may be considered since the association between individual characteristics (e.g., education) and recall error increases with the length of the recall period.