Assessment Methods for Patient-Reported Outcomes

The methods used to collect information on patient-reported outcomes (PROs) can affect the validity, reliability and sensitivity of the data. This review examines the influence of a variety of methodological issues that occur. In particular, when patients are asked to rely on their memory to aggregate and summarize their experience, a variety of inaccuracies and biases can affect the data. As the extent and magnitude of recall bias have become more well-known, researchers have increasingly turned toward collecting data in the field, closer in time to events and experiences of interest. Diary methods require patients to self-monitor their experiences, disease episodes and healthcare utilization over time. The collection of diary data from patients places a premium on adherence to the data collection protocol. Recent evidence suggests that patients routinely fail to adhere to diary protocols, thus introducing retrospective error and biases into the data. Reasons for patients' non-adherence to data collection protocols include their desire to appear to be `good' patients which can result in back-filling PRO entries before a site visit, simply forgetting, and data collection methods that fail to help patients be adherent to the data collection protocol. Principles that can be used to enhance patient adherence to PRO data collection methods include good patient training, creating simple and intuitive user interfaces for PRO assessments, and actively driving the protocol by helping patients remember to complete PRO measures as required by the protocol.