The article examines different ways to predict inflation using estimates of the output gap. While some measures of the output gap are good at predicting inflation after the fact, they don't work as well in real-time. Simple models using past inflation and output growth are more effective at forecasting inflation. The accuracy of these forecasts can vary depending on whether inflation is high or low at the time. This suggests that the output gap concept may not be very helpful for predicting inflation in practice.