This report was commissioned through the Department for Work and Pensions' Families and Children Strategic Analysis Programme (FACSAP). It examines methods that could potentially be used to explore the link between mothers' demand for childcare and their employment. Several approaches are examined, including: learning from evaluations of existing programmes; the scope for natural experiments and the potential for reduced form and structural modelling of key relationships. The report focuses on methodology but in doing so presents findings from existing studies in the area, most of which are from the United States.