Choice of response scale for health measurement: comparison of 4, 5, and 7-point scales and visual analog scale.

To compare the feasibility of response scales with different numbers of steps for measuring health status, we assessed the ease of completing 4, 5, and 7-point scales and a visual analog scale. Four forms of the questionnaire, each of which consisted of the same ten questions about health status, but with a different type of scale among the four above mentioned, were given to 48 patients with a variety of conditions and diagnoses. The forms were attached together and the order in which they were presented was systematically varied considering permutations of forms. Respondents were asked to complete the forms following the order of the sheets. The 5-point scale form was most commonly chosen as the easiest to complete, and item omission was least frequent with this form. Similar high- reliability results in terms of Cronbach's alpha were achieved for each of the four forms. An additional survey among 153 patients confirmed the results of the first survey. The selection of the easiest scale to complete varied by sex (men preferred the 7-point scale), but was not affected by the conditions or diagnoses of the patients. The study suggests that the 5-point scale is most useful for measuring health status.