Labor Supply, Hours Constraints, and Job Mobility
利用已婚女性样本，通过比较换工作与不换工作者工时对偏好变化的反应差异，检验雇主是否限制工时选择。
If hours can be freely varied within jobs, the effect on hours of changes in preferences for those who do change jobs should be similar to the effect on hours for those who do not change jobs. Conversely, if employers restrict hours choices, then changes in preferences should affect hours more strongly when the job changes than when it does not change. For a sample of married women we find that changes in many of the labor supply preference variables produce much larger effects on hours when the job changes.