Guttman scale analysis of the distance vision scale

Abstract

PURPOSE. The Distance Vision Scale (DVS) is a self-assessment of visual acuity (VA). Like VA testing in which letter reading becomes progressively difficult through the test, DVS questions have a hierarchy of difficulty (Guttman scale). The aims were to determine whether the DVS fulfills Guttman scaling criteria and to test the relationship between DVS score and VA in a cataract population. METHODS. Responses of 113 participants to the DVS were subjected to Guttman analysis. Standard criteria of scalability were evaluated that included the coefficient of reproducibility (CR), minimal marginal reproducibility (MMR), and coefficient of scalability (CS). The relationship between total item scor..