How to fight tax evasion

Tax evasion is a serious problem in developing countries because of the tiny administrative capacity of authorities and the size of the informal sector. Even in more developed economies, say, the Southern European ones, tax evasion is part of daily life. Again, administrative capacity is lacking. One could even argue it is a problem in the United States seeing the tiny auditing staff of tax authorities and the complexity of the tax code. Tax auditors have thus to define priorities.

Mirco Tonin studies the rules that Italy and Bulgaria instituted. In Italy, businesses and self-employed people reporting revenues below some level are subject to higher scrutiny. The idea is thus not to go after those who declare to be big fish, but rather those who may hide it. And making it known that there is such a threshold induces people to declare more to tax authorities. In Bulgaria, authorities are after employees and firms that declare too little in social security contributions. This is also forcing them to declare more to avoid scrutiny.

Tonin uses a model of imperfect monitoring to figure out whether such threshold rules make sense. And yes, they improve tax revenue, as those who have higher true income declare more than the threshold, and those below become more truthful. Now all you need to do is figure out where to put the threshold to equalize marginal tax revenue and marginal auditing cost, possibly adjusted by the dead-weight cost of taxation and for observable characteristics of the tax payer.

Are consumption taxes more equitable?

There is no doubt that consumption taxes are more efficient that labor income or capital income taxes, because they do not punish activities one would like to see promoted in an economy (labor supply, investment). But they are widely regarded as unfair, as the consumption share of income is higher for poor people. Hence the implementation of exclusions for essential goods where consumption taxes exist, in order the achieve some tax progressivity.

Isabel Correia claims that switching from income taxes to consumption tax can lead to less inequality even in the absence of lump sum transfers. This is a very counterintuitive result, and this is probably the reason why it made it into the American Economic Review (Yes, I know, I am breaking a trend here). But despite my best efforts, I still do not understand how this could happens, and the article provides very little in terms of explanation. Not only is no intuition provided, but the idea of using Gorman aggregation to reduce the model to a representative agent model seems wrong in this context. If anybody has read and understood the article, please help me here.