The study looked at how people in Hungary changed their income in response to tax changes in 2005. They found that when taxes went up, people adjusted their income by a small amount. Higher-income earners were more sensitive to tax changes than lower-income earners. The researchers also looked at what would happen if Hungary switched to a flat tax system. They found that while the government could make a bit more money, it would also increase income inequality and hurt middle-income earners the most.