Oxyopia Abstract

February 21, 2008
Friday, 4:00 PM
489 Minor Hall

Faculty Search Candidate

Title

From Rash to Rasch – The Evolution of Patient-Reported Outcomes

Abstract

A key component of the evidence-based medicine movement is the measurement of outcome from the patient's point of view. So called - patient-reported outcomes - usually take the form of a questionnaire. The clinician scientist needs to include a questionnaire as part of the design of a clinical study; especially for translational research. While a clinician scientist may be an expert in the clinical testing that would best evaluate the outcome of the intervention under trial, they may not be expert in questionnaires. But they have to be, a poor choice of patient-reported outcome measurement, may corrupt an otherwise well-designed study. The field of questionnaire science is not more static than that of vision science. Over the two decades, great advances have been made to questionnaire measurement quality using various models of item response theory, most commonly Rasch analysis. These mathematical models estimate the calibration of persons and items (questions) along a latent trait which represents a linear measure. Thereby, Rasch analysis improves the precision of measurement by removing non-linearities inherent in simple summary scoring. Rasch analysis also improves the accuracy of the measurement by providing insight into which items should be included in a questionnaire. Optometry has benefited from these advances in questionnaire science with Rasch scaled instruments now available for measuring outcomes for refractive correction (including contact lenses and refractive surgery), low vision care, cataract surgery, treatments for keratoconus and dry eye. The development of some of these instruments, their application and their demonstrable advantages will be covered in this presentation.

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