The impact of taxes on female labour supply

There is little agreement in economics on the factors influencing labour supply and hence on the impact of taxes. Within the marginal model, real wages and incomes are directing people's labour market behaviour independent of time and space, whereas the human resources approach takes account of the social environment and past behaviour. Even if strong assumptions are made, the neoclassical theory cannot predict the outcome of a wage increase. The labour supply response depends on the relative strengths of the substitution and the income effect. Since nonparticipation in the labour market is explained by a reservation wage being higher than the market wage, this is the only situation in which neoclassical theory would predict a rise in labour force participation with a wage increase. This case occured in a ‘natural experiment’ in Sweden. The Swedish tax system changed in 1971 from joint to separate taxation of spouses resulting in a substantial increase in the net wage of married women. This article investigates the impact of the change in the Swedish tax system on female labour force participation, concluding that it cannot explain the substantial rise in the participation rates of Swedish women. This is a significant result, questioning standard neoclassical theory and supporting the more institutional views of human labour market behaviour. That is that time and space as well as the social environment are important when analyzing labour supply. This will have consequences for international comparisons. Only factors which explain developments within one country might be relevant for explaining international differences, e.g. in labour force participation.