"If you have the flu symptoms, your asymptomatic spouse may better answer the willingness-to-pay question". Evidence from a double-bounded dichotomous choice model with heterogeneous anchoring.
The small sample size of contingent valuation (CV) surveys conducted in patients may have limited the use of the single-bounded (SB) dichotomous choice format which is recommended in environmental economics. In this paper, we explore two ways to increase the statistical efficiency of the SB format: (1) by the inclusion of proxies in addition to patients; (2) by the addition of a follow-up dichotomous question, i.e. the double-bounded (DB) dichotomous choice format. We found that patients (n=223) and spouses (n=64) answering on behalf of the patient had on average a similar willingness-to-pay for earlier alleviation of flu symptoms. However, a patient was significantly more likely to anchor his/her answer on the first bid as compared to a spouse. Finally, our original DB model with shift effect and heterogeneous anchoring reconciled the discrepancies found in willingness-to-pay statistics between SB and DB models in keeping with increased statistical efficiency.
Center for Health Policy, Freeman Spogli Institute for International Studies/Center for Primary Care & Outcomes Research, School of Medicine, Stanford University, CA 94305-6019, USA. schwarzi@stanford.edu
Michaël
M
Schwarzinger
Fabrice
F
Carrat
Stéphane
S
Luchini
D000328:Adult; D002755:Choice Behavior; D005260:Female; D005382:Financing, Personal; D005602:France; D006801:Humans; D007251:Influenza, Human / Q000191:economics* / Q000628:therapy; D008297:Male; D017059:Models, Econometric; D010342:Patient Acceptance of Health Care; D019727:Proxy; D018454:Spouses