Tax changes in Israel between 1991-2012 were studied to see how they affect tax revenue. By looking at forecasts made before the changes, researchers found that tax changes only bring in about 70% of the expected revenue. The impact on revenue peaks two years after the change and then decreases. Contrary to popular belief, lowering tax rates doesn't always lead to higher revenue. Corporate income tax changes bring in 90% of expected revenue after two years, while personal income tax changes only bring in 65%. Lowering personal income tax rates can actually decrease average wages in the economy.