A simplified formula is: r = p + 0.5y + 0.5 (p - 2) + 2 (after Tobin, 1998)
- r = the short term interest rate in percentage terms per annum.
- p = the rate of inflation over the previous four quarters.
- y = the difference between real GDP from potential output.
- This assumes that target inflation is 2% and equilibrium real interest rate is 2%
Example of Taylor Rule:
- If inflation were to rise by 1%, the Taylor response would be to raise the interest rate by about 1.5%
- If GDP falls by 1% relative long run trend rate, then the Taylor response is to cut the interest rate by about 0.5%
- Basically, higher growth and inflationary pressures require higher interest rates to reduce economic activity. Lower growth and a fall in inflation require lower interest rates to boost spending.
Interest Rates Too Low in US Using Taylor Rule
The interesting thing is what the Taylor rule says about current interest rates. Since GDP in US has collapsed by - 4% (when growth trend is about 2%) it means that GDP is much lower than potential. Paul Krugman estimated that using the Taylor rule, the US should give a nominal interest rate of -7%. This indicates why the Federal Reserve are having to resort to quantitative easing. They can't cut interest rates below 0%, so they need to resort to unorthodox measures to boost the economy.