Improving task comprehension in the measurement of health state preferences. A trial of informational cartoon figures and a paired-comparison task.

Information concerning people's relative preferences for health care outcomes is usually obtained using questionnaires which ask subjects to imagine health states of various kinds. When using illness- or treatment-specific states, elaborate descriptions of patients' quality of life may adequately convey to the rater a sense of the real situation. Such descriptions are not possible with generic questionnaires, which frame outcomes in general terms, such as pain, limits on activities, etc. This study evaluated two methods for facilitating task comprehension with generic preference-assessment instruments: (1) use of informational figures that provide visual representations of the described health state, and (2) measurement of preferences by means of a paired-comparison task. The use of figures did not change rating variance or the number of counter-intuitive ratings, but did improve one-week test-retest reliability. Paired comparisons had reliability comparable to the direct rating tasks and reduced the number of counter-intuitive ratings, although not to a statistically significantly extent.