Willingness-to-pay for caregivers of children with asthma or wheezing conditions
Authors Stefan Walzer, Peter Zweifel
Published 15 March 2007 Volume 2007:3(1) Pages 157—165
Stefan Walzer1, Peter Zweifel2
1Analytica International, Untere Herrenstrasse 25, 79539 Loerrach, Germany; 2University of Zurich, Socioeconomic Institute, Hottingerstr. 10, 8032 Zurich, Switzerland
Background: Nearly 5 million children in the United States are affected by asthma, which is more than 5% of the population younger than 18 years. In children four years or younger, the prevalence increased 160% from 1980 to 1994. There are several effective drugs that relieve the symptoms of asthma and others are currently being developed, but even when these medications are prescribed, they may be underutilized because parents fear the possibility of adverse events. There is no knowledge whether caregivers would be willing to pay (WTP) for safe and effective medications in general.
Material and methods: In a conjoint analysis, the status quo and hypothetical treatment options are defined by four attributes: episode-free days, risk of exacerbation, information available on the long-term impact of the treatment, and out-of-pocket expenses. Based on random utility theory, a binary purchase decision equation is specified and estimated using probit. Several tests were performed with regards to the scaling of the attribute variables, the linearity of the utility function used, and the derivation of a final model.
Results and conclusions: Marginal willingness-to-pay per month for 20 additional episode-free days due to a new treatment turns out to be US$6.00. An interesting question from the (industry) policy point of view for possible new products is the amount of WTP for the product as a whole. Assuming that the final model is correctly specified, the (negative) constant may be interpreted as indicating that caregivers feel confident with the asthma treatment options already on the market and having hence not a positive relation to a new treatment.
Keywords: willingness-to-pay; conjoint analysis, preference study, health economics, discrete-choice analysis