One fruitful and much used approach to assess the effect of tax reforms is to calculate the elasticity of taxable income sometimes labelled as the new tax responsiveness literature. Early contributions to this literature are the work conducted by Lindsey (1987) and Feldstein (1995). More recent contributions are Goolsbee (1999;2000), Auten and Carroll (1999) and Gruber and Saez (2002). All these contributions, however, share the common fact that they are studies on US data. Looking into non-US data, the t wo earliest contributions were Sillamaa and Veall (2001) and Aarbu and Thoresen (2001), respectively on Canadian and Norwegian data. The driving idea behind these studies is to utilize the fact that tax reforms can be seen as natural experiments in the se nse that groups in the population are affected differently by tax changes. The differences-in-differences estimator, which measures the elasticity of taxable income, can be used within such an approach.
Our study from 2001 both discussed and tested for income shifting but we were not able to confirm such behavioural effects. This might be explained by the fact that the instrument we used in order to control for income shifting activities (including organisational shifts) was weak.
We are now in a com pletely different situation with respect to data. This project will exploit data from Income Statistics for Persons and Families , which includes register-based information about the whole population. Most importantly, we have now connected these data to information from the newly established Register of Shareholders (Aksjonærregisteret) and with the End of the Year Certificate Register (Lønns- og trekkoppgaveregisteret). Such information enhances possibilities to control for income shifting activities.
In this project we also suggest to discuss the results from the new tax responsiveness literature in relation to results from structural labour supply models. We think this issue deserves more attention.