There was a second economics professor who also made similar claims although I found them a bit harder to evaluate as the example was not as clear. This argument seemed to be more about how hard this person would find it to make cutbacks rather than a specific example of how he would become less productive.
Yesterday,Noahpinion linked to a great article by Karl Smith that went to the heart of this discussion. The argument was whether tax increases (at the sort of marginal rates we currently have) really depress productivity. Karl Smith made a number of arguments that were worth considering, including:
Third, high income people don’t seem to be working that much more than low income people despite the fact that a natural propensity towards work can make one high income.
Indeed, the data show us that low income folks used to work a little more, but now they work a little less than high income folks. Yet, if the income and substitution effects were balanced for each person we would still expect higher income people to work more.
That’s because working hard can lead to more education, more experience and more promotions. Being hard working is also associated with having a conscientious personality type which is itself more valuable.
So if someone was simply born with a stronger propensity to work, we would expect that person to earn more income per hour. Thus we when look at the data we should see that all these high income people are working lots of hours.
Yet, we actually don’t see that. We see only a mild effect and even then that effect is not robust over time. Sometimes, high income folks are working less.
But the piece is a must read in the entirety. The key argument here, though, is whether the extremely small tax increases that are under discussion (a raise in the marginal tax rate for the highest income bracket from 36% to 39.6%) is really likely to make high income Americans less productive. Because if these tax increases don't disincent work and we accept that government finances really are a mess then the tax hikes seem to be a logical way to "share the cost of these increases".
But I also think that these points don't necessarily go far enough. Are we really convinced that a small decrease in productivity among the wealthy will be that devastating? What is the source of productivity in the American economy? Is it highly paid CEOs, hedge fund managers, lawyers and medical doctors, or is it the majority of workers who drive productivity?
I think it is essential to get this correct. A top down model of an economy (where the people at the top make the key decisions and are responsible for the output) did poorly in Soviet Russia. A bottom up theory of economic gains seems to make a lot more sense and that suggests that small productivity losses among the wealthy are not a serious concern.
It is worth emphasizing that, at this time, I am aware of two proposals to increase the tax rates of the wealthy: increasing the amount of wages on which FICA can be charged and returning to Clinton-era tax rates. Neither of these increases is a vast change in the marginal tax rate of this group. Clearly there are tax increases that would cause issues, but we can handle those when they show up and not now when all of the possible rates under discussion are sane.
The last example that people tend to bring up is innovation and how important it is to reward innovators. Now, as part of a first principle I would like to point out that the innovator is not always the person who profits the most from an invention (consider Nikola Tesla). But it is also worth noting, as Mark points out, that copyright law already provides enormous rewards for intellectual property holders.
So I think we should look to balance harms. Recent events have included layoffs of government workers into a economy with an extremely high unemployment rate. Are we sure that the consequences of a large body of long term unemployed workers will be better than that of small increases in tax rates?