Empirical implementation of labour supply theories is usually based on realized labour market behaviour. This requires strong assumptions about the impact of labour demand. A possibility to avoid these assumptions is to make use of subjective data on desired labour supply. In this paper we investigate whether respondents’ answers to survey questions on the desired number of working hours contain additional information on the preferences of the individuals. Using panel data for the Netherlands, we analyze whether deviations between desired hours and actual hours of work help to predict future job changes or changes in hours worked. We use parametric and recently developed nonparametric tests. The results suggest that subjective information on desired working hours are helpful in explaining female labour supply. For males the evidence is mixed.