The article tests popular economic models to see if they accurately predict how people's expectations affect the economy. By analyzing real data and using a special approach, the researchers found that the models often fail to match up with what actually happens. When the models try to include people's expectations, they have to give up some of their strict rules to fit the data better. Different ways of predicting expectations can help the models work better, but there are still some mistakes in how they handle expectations compared to real-world results.