Laffer curve is simplistic in that it assumes a single tax rate and a single labor supply. Actual systems of public finance are more complex, and there is serious doubt about the relevance of considering a single marginal tax rate. In addition, revenue may well be a multivalued function of tax rate; for instance, an increase in tax rate to a certain percentage may not result in the same revenue as a decrease in tax rate to the same percentage (a kind of hysteresis). Furthermore, the Laffer curve does not take explicitly into account the nature of the tax avoidance taking place.
Laffer curve Jude Wanniski, who was also present at the meeting. The basic concept was not new; Laffer himself notes antecedents in the writings of the 14th-century social philosopher Ibn Khaldun and others. Laffer does not claim to have invented the concept; he notes that there are antecedents, including in the "Muqaddimah" by 14th-century Tunisian scholar Ibn Khaldun, and in the writings of John Maynard Keynes. It was not until the 1970s that Laffer's name began to be associated with the idea. The term "Laffer curve" was reportedly coined by Jude Wanniski (a writer for "The Wall Street Journal") after a 1974