The article discusses how economists study the effects of monetary policy on the economy. They look at different models and data to understand how changes in interest rates and money supply impact things like inflation and economic growth. Some older models didn't work well because they didn't consider both theory and data. Newer approaches focus on statistical models and finding the best way to use data in their analysis. One interesting finding is that a type of statistical model called a VAR can be used to approximate the results of a more complex economic model. The researchers are still figuring out which type of VAR is best for studying monetary policy.