title: Contingent valuation scenarios for chronic illnesses: the case of childhood asthma.
abstract: OBJECTIVE
  We use a contingent valuation (CV) study of childhood asthma to discuss a central issue in designing CV studies of chronic illness-the need for a detailed, realistic scenario that minimizes confounding factors-and show how to address this issue. We apply our methodology to estimate households' willingness to pay (WTP) for reductions in asthma morbidity.
  
  
  METHODS
  By using a combination of focus groups, revealed preference surveys, and epidemiological surveys, we gathered information on health status, attitudes, and beliefs regarding asthma, risk-averting behaviors, perceptions of these behaviors, and household socioeconomic characteristics. We used this information to design a CV survey that we extensively tested for validity. In the survey, we elicited participants' WTP for a hypothetical device that would reduce symptom-days by improving asthma management; these data enabled us to estimate household WTP by using a variety of econometric models.
  
  
  RESULTS
  Our analysis of households with children with asthma yielded the following conclusions: the scenario should address both physical asthma symptoms and the psychosocial stress of managing a chronic illness; the survey should measure household perceptions of the burden of asthma in addition to objective measures such as symptom-days; and the scenario should not involve substantial behavioral changes or a new medication, to avoid confounding household preferences with unrelated attributes of the scenario. Our primary models estimated mean household WTP for a 50% reduction in symptom-days (and accompanying reductions in psychosocial stress) at $56.48 to $64.84 per month.
  
  
  CONCLUSIONS
  Our methodology can be used to inform CV studies of chronic illness. Our WTP estimates can help regulatory agencies assess a wide range of policies that affect the incidence or severity of asthma.
authors.affiliation: Department of Resource Economics, University of Massachusetts, Amherst, Amherst, MA 01003, USA. sylvbrandt@gmail.com
authors.forename: Sylvia
authors.initials: S
authors.lastname: Brandt
authors.forename: Felipe
authors.initials: F
authors.lastname: Vásquez Lavín
authors.forename: Michael
authors.initials: M
authors.lastname: Hanemann
mesh_terms: D000293:Adolescent; D001249:Asthma / Q000191:economics* / Q000523:psychology*; D002648:Child; D002908:Chronic Disease; D015986:Confounding Factors, Epidemiologic; D005260:Female; D005382:Financing, Personal; D015438:Health Behavior; D007722:Health Knowledge, Attitudes, Practice; D006304:Health Status; D006801:Humans; D008297:Male; D018803:Models, Economic; D010342:Patient Acceptance of Health Care / Q000706:statistics & numerical data*; D012720:Severity of Illness Index; D012959:Socioeconomic Factors; D013315:Stress, Psychological / Q000453:epidemiology / Q000517:prevention & control