The study looked at how inflation and unemployment are related in Indonesia from 1990 to 2019. It found that when expected inflation is negative, it makes it hard for the central bank to control interest rates during economic shocks. If the central bank reduces money supply, it leads to lower output, higher unemployment, and inflation. But increasing money supply doesn't lead to significant output growth. To boost output and purchasing power, the central bank should keep expanding money supply for a longer time. This will eventually make expected inflation positive, as suggested by the modified Phillips curve.