Does recall period matter? Comparing PROMIS physical function with no recall, 24-hr recall, and 7-day recall

Purpose To evaluate the influence of recall periods on the assessment of physical function, we compared, in cancer and general population samples, the standard administration of PROMIS Physical Function items without a recall period to administrations with 24-hour and 7-day recall periods. Methods We administered 31 items from the PROMIS Physical Function v2.0 item bank to 2400 respondents (n = 1001 with cancer; n = 1399 from the general population). Respondents were randomly assigned to one of three recall conditions (no recall, 24-hours, or 7-days) and one of two "reminder" conditions (with recall periods presented only at the start of the survey or with every item). We assessed items for potential differential item functioning (DIF) by recall time period. We then tested recall and reminder effects with analysis of variance controlling for demographics, English fluency, and co-morbidities. Results Based on conservative pre-set criteria, no items were flagged for recall time period-related DIF. Using analysis of variance, each condition was compared to the standard PROMIS administration for Physical Function (no recall period). There was no evidence of significant differences among groups in the cancer sample. In the general population sample, only the 24-hour recall condition with reminders was significantly different from the "no recall" PROMIS standard. At the item level, for both samples, the number of items with non-trivial effect size differences across conditions was minimal. Conclusions Compared to no recall, the use of a recall period has little to no effect upon PROMIS physical function responses or scores. We recommend that PROMIS Physical Function be administered with the standard PROMIS "no recall" period.