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.
Immigration to the United States An internal study by the Department of Health and Human Services under the Trump administration, which was suppressed and not shown to the public, found that refugees to the United States brought in $63 billion more in government revenues than they cost the government. According to labor economist Giovanni Peri, the existing literature suggests that there are no economic reasons why the American labor market could not easily absorb 100,000 Syrian refugees in a year. Refugees integrate more slowly into host countries' labor markets than labor migrants, in part due to the loss and depreciation of human capital and credentials