In an article in the Wall Street Journal, Arthur Laffer argued that, since 1960, the introduction of state income taxes reduced the relative size of a state’s gross state product and its relative per capita personal income. This paper criticizes Laffer’s conclusions on a number of grounds. 1. He uses incorrect figures for per capita income. In fact, relative per capita income rose in a majority of states that introduced an income tax since 1960. 2. The results are not clear when a state’s data is compared to other states in its region, rather than to the United States as a whole. Since many of the states that introduced an income tax were hard-hit by the decline in the economy (such as Illinois, Indiana, Michigan, Ohio, West Virginia), the comparison to the United States as a whole is misleading. 3. Even if the data were accurate, the argument for causation would be quite weak because so many other factors affect a state’s economic health.
Shakow, David J., "Does It Hurt a State To Introduce an Income Tax?" (2010). Faculty Scholarship at Penn Law. 343.