The duration effect: a link between TTO and VAS values
利用英国全国代表性数据，检验了健康状态价值是否随持续时间变化，发现最优健康状态呈负相关（公平论据），较差健康状态呈正相关（适应），否定了恒定比例假设。
The value of a health state may depend on how long an individual has had to endure the health state (i.e. hedonic load). In this paper, we test the constant proportionality (CP) assumption and determine the sign of relationship between duration and health state value for 42 health states using the nationally representative data from the United Kingdom Measurement and Valuation of Health study. The results reject the CP assumption and suggest that the relationship is negative for optimal health (i.e. fair innings argument) and that the relationship is positive for poorer health states (i.e. adaptation). We find no evidence of the maximum endurable time hypothesis using these data. This evidence on the duration effect has important implications for outcomes research and the economic evaluation of interventions.