In scientific literature, two key parameters have been established measuring the reaction to income tax changes: labour supply elasticities on the one hand and the elasticity of taxable income on the other. Despite a considerable number of empirical studies on this topic in the past few decades, there is still a lack of clarity about "correct" elasticities. This meta-study provides an overview of the present estimates of both elasticities. Special emphasis is placed on the isolation and analysis of the systematic influence of various estimates.