On Integrating Income Tax and Unemployment Insurance in Models of Labour Supply by Shelley Phipps and Lars Osberg 1 March 1991 This paper represents joint research, the order of names being established by the time- 1 honoured expedient of tossing a coin. We would like to thank Zhengxi Lin for his exemplary work in this project and the Social Sciences & Humanities Research Council of Canada for its financial support.