The study looked at the US economy from 1990 to 2009 to understand how prices and wages change over time. They found that wages tend to stay the same even when other things are changing, which can affect how the economy works. This suggests that it's more common for wages to be rigid than prices, meaning that labor markets play a big role in how the economy behaves. This could be because of things like people's expectations or the way wage contracts are set up. Overall, the study shows that understanding how wages behave is important for explaining how the economy goes up and down.