We investigate whether the value of time (VOT) depends on when the corresponding preferences are measured: in advance, just before, or after the time period for which the time preferences are being evaluated. We find that the VOT is highest when elicited just before the time period. This is an indication of the VOT being affected by time-inconsistent, and more specifically, present-biased preferences. We argue that this result may explain why time valuations based on stated preference (SP) data are typically found to be lower than those based on revealed preference (RP) data: most RP surveys evaluate the preferences of respondents close to the time period for which the preferences are being measured, whereas the time instances for which preferences are evaluated in SP surveys tend to be more abstract, or referencing past or future time periods.

我们调查时间（VOT）的值是否取决于测量相应偏好的时间：在评估时间偏好的时间段之前，之前或之后。我们发现，在该时间段之前触发时，VOT最高。这表明VOT受时间不一致的影响，更具体地说，受到当前偏爱的偏好的影响。我们认为，该结果可以解释为什么通常会发现基于陈述性偏好（SP）数据的时间价值要低于基于显性偏好（RP）数据的时间价值：大多数RP调查都评估了接近于该时间段的受访者的偏好偏好被测量，而在SP调查中评估偏好的时间实例往往更抽象，或者参考过去或将来的时间段。