[Acceptance and understandability of various methods of health valuations for the chronically ill: willingness to pay, visual analogue scale and rating scale]

Objective of the study: Health valuations are one way of measuring patient preferences with respect to the results of their treatment. The study examines three different methods of health valuations - willingness to pay (WTP), visual analogue scale (VAS), and a rating question for evaluating the subjective significance. The goal is to test the understandability and acceptance of these methods for implementation in questionnaires.

Method: In various rehabilitation centres, a total of six focus groups were conducted with 5-9 patients each with a mean age of 57.1 years. The illnesses considered were chronic-ischaemic heart disease, chronic back pain, and breast cancer. Patients filled out a questionnaire that was then discussed in the group. In addition to the quantitative evaluation of the data in the questionnaire, a qualitative analysis of the contents of the group discussion protocols was made.

Results: We have results from a total of 42 patients. 14.6% of the patients had "great difficulties" understanding the WTP or rated it as "completely incomprehensible"; this value was 7.3% for VAS and 0% for the rating scale. With respect to acceptance, 31.0% of the patients indicated that they were "not really" or "not at all" willing to answer such a WTP question in a questionnaire; this was 6.6% for the VAS, and again 0% for the rating scale. The qualitative analysis provided an indication as to why some patients view the WTP question in particular in a negative light. Many difficulties in understanding it were related to the formulation of the question and the structure of the questionnaire. However, the patients' statements also made it apparent that the hypothetical nature of the WTP questionnaire was not always recognised. The most frequent reason for the lack of acceptance of the WTP was the patients' fear of negative financial consequences of their responses.

Discussion: With respect to understandability and acceptance, VAS questions appear to be better suited for reflecting patient preferences than WTP questions. The rating scale for assessing the personally estimated importance was understandable, but had poor distribution properties and was considered by patients to be superfluous.