Recalling what we thought we knew about recall periods: a qualitative descriptive study of how adults diagnosed with cancer use recall periods for patient-reported outcome items about physical function

Objectives: In cancer studies, assessment of patients' physical function can provide insight into cancer-related symptoms and the side effects of treatment. Physical function can be assessed using patient-reported outcome measures (PROMs), which may or may not include a recall period-the amount of time the questionnaire asks the respondent to think back to answer the questions. More understanding is needed about how patients interpret and respond to items posed with different recall periods, and which recall period they actually use.

Study design and setting: We conducted a qualitative study with 72 adults diagnosed with cancer to describe response processes when answering PROM items about physical function.

Results: When describing their physical function during concept elicitation interviews, most participants recalled their functioning over 1 month or more. When presented with PROM items with no recall period, the most used period was more than 4 weeks. When presented with a 7-day recall, the most used period was 7 days. However, almost 30% of responses used recall periods greater than 1 week.

Conclusion: Including a 7-day recall period improves recall consistency for patients when answering physical function PROM items, but there is still room for improvement. The inaccuracy of recall for PROMs in clinical trials influences the ability to calculate the change in treatment outcomes over time and may conceal or emphasize actual treatment effects.