Department of Resource Economics, University of Massachusetts, Amherst, Amherst, MA 01003, USA.
Value Health. 2012 Dec;15(8):1077-83. doi: 10.1016/j.jval.2012.07.006. Epub 2012 Oct 1.
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.
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.
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.
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.
我们利用儿童哮喘的条件价值评估(CV)研究来讨论设计慢性病 CV 研究中的一个核心问题——需要一个详细、现实的方案来最小化混杂因素,并展示如何解决这个问题。我们应用我们的方法来估计家庭对降低哮喘发病率的支付意愿(WTP)。
通过结合焦点小组、揭示偏好调查和流行病学调查,我们收集了有关健康状况、对哮喘的态度和信念、避险行为、对这些行为的看法以及家庭社会经济特征的信息。我们利用这些信息设计了一个 CV 调查,并对其进行了广泛的有效性测试。在调查中,我们询问了参与者对一种假设设备的 WTP,该设备通过改善哮喘管理来减少症状天数;这些数据使我们能够使用各种计量经济学模型来估计家庭的 WTP。
我们对有哮喘儿童的家庭进行的分析得出以下结论:方案应同时解决身体哮喘症状和管理慢性病的心理社会压力;调查除了症状天数等客观指标外,还应衡量家庭对哮喘负担的看法;方案不应涉及实质性的行为改变或新的药物,以避免将家庭偏好与方案的无关属性混淆。我们的主要模型估计,家庭对症状天数减少 50%(并相应减少心理社会压力)的支付意愿平均值为每月 56.48 至 64.84 美元。
我们的方法可用于为慢性病的 CV 研究提供信息。我们的 WTP 估计值可以帮助监管机构评估影响哮喘发病率或严重程度的各种政策。