consumption tax's rate): the effects of the two taxes are the same. A tax effectively changes the relative prices of products. Therefore, most economists, especially neoclassical economists, argue that taxation creates market distortion and results in economic inefficiency unless there are (positive or negative) externalities associated with the activities that are taxed that need to be internalized to reach an efficient market outcome. They have therefore sought to identify the kind of tax system that would minimize this distortion. Recent scholarship suggests that in the United States of America, the federal government effectively taxes investments in higher education more heavily than it subsidizes higher education, thereby contributing to a shortage of skilled workers and unusually high differences in pre-tax earnings between highly educated and less-educated workers. Taxes can even have effects on labor supply: we can consider a model in which the consumer chooses the number of hours spent working and the amount spent on consumption. Let us suppose that only one good exists and no income is saved. Consumers have a given number of hours (H) that is divided between work (L) and free time (F = H - L). The hourly wage is called w and it tells us the free time's opportunity cost, i.e. the income to which the individual renounces consuming an additional hour of free time. Consumption and hours of work have a positive relationship, more hours of work mean more earnings and, assuming that workers don't save money, more earnings imply an increase in consumption (Y = C = wL). Free time and consumption can be considered as two normal goods (workers have to decide between working one hour more, that would mean consuming more or having one more hour of free time) and the budget constraint is negatively inclined (Y = w(H - F)). The indifference curve related to these two goods has a negative slope and free time becomes more and more important with high levels of consumption. This is because a high level of consumption means that people are already spending many hours working, so, in this situation, they need more free time than consume and it implies that they have to be paid with a higher salary to work an additional hour. A proportional income tax, changing budget constraint's slope (now Y = w(1 - t)(H - F)), implies both substitution and income effects. The problem now is that the