What is something economists need to know the least in order to effectively fine tune the economy?

a. potential income/output.

b. the cpi.

c. the multiplier.

d. aggregate equilibrium income/output five years ago?

b. the cpi is what the economists need to know the least.

CPI stands for Consumer Price index which measures the change in price level based on the goods and services purhased by consumers. The Costumer price Index will not affect the economic situation because it only calculate the measurement of the price changes of a basket of goods over time.