Grant: Operating Grant

Patient-reported outcome measures (PROMs) are used by patients to describe their health, including their quality of life, pain, fatigue, and depression. PROMs are used by physicians, nurses, and healthcare decision makers to describe the outcomes of care from the patient's point of view. In order to contribute to improved patient care, PROMs must be valid (i.e., measure what they are supposed to measure) and reliable (i.e., measure the same thing over time and for different types of patients). Sometimes, patient responses on PROMs are not consistent with what was expected. These inconsistencies may occur because patients with similar health outcomes may not understand or interpret questions about their health in the same way (differential item functioning), or their interpretations may change over time (response shift). While these differences in interpretation and "response shifts" could be a result of positive adaptations to health challenges, they are often difficult to detect and, if ignored, could lead to incorrect interpretations about outcomes of care based on PROMs information. Our research focuses on methods to test for the effects of response shift and differential patient interpretations in the measurement of PROMs. Our goal is to develop and compare methods to test for these effects. We will apply the methods to existing registry data for patients having elective surgery for hip or knee replacements, a healthcare intervention that can have a large impact on quality of life. The overall goal of our research is to improve the ability to accurately interpret patient-reported information when measuring the effectiveness of the healthcare system.