Comparison of Modes of Administration and Alternative Formats for Eliciting Societal Preferences for Burden of Illness.

BACKGROUND: Proposals for value-based assessment, made by the National Institute of Health and Care Excellence (NICE) in the UK, recommended that burden of illness (BOI) should be used to weight QALY gain. This paper explores some of the methodological issues in eliciting societal preferences for BOI.

AIMS: This study explores the impact of mode of administration and framing in a survey for eliciting societal preferences for BOI.

METHODS: A pairwise comparison survey with six arms was conducted online and via face-to-face interviews, involving two different wordings of questions and the inclusion/exclusion of pictures. Respondents were asked which of two patient groups they thought a publically funded health service should treat, where the groups varied by life expectancy without treatment, health-related quality of life (HRQOL) without treatment, survival gain from treatment, and HRQOL gain from treatment. Responses across different modes of administration, wording and use of pictures were compared using chi-squared tests and probit regression analysis controlling for respondent socio-demographic characteristics.

RESULTS: The sample contained 371 respondents: 69 were interviewed and 302 completed the questionnaire online. There were some differences in socio-demographic characteristics across the online and interview samples. Online respondents were less likely to choose the group with higher BOI and more likely to treat those with a higher QALY gain, but there were no statistically significant differences by wording or the inclusion of pictures for the majority of questions. Regression analysis confirmed these results. Respondents chose to treat the group with larger treatment gain, but there was little support for treating the group with higher BOI. Respondents also preferred to treat the group with treatment gains in life expectancy rather than HRQOL.

CONCLUSIONS: Mode of administration did impact on responses, whereas question wording and pictures did not impact on responses, even after controlling for the socio-demographic characteristics of respondents in the regression analysis.