Most macroeconomists replace the equation of exchange with equations for the demand for money which describe more regular and predictable economic behavior. However, predictability (or the lack thereof) of the velocity of money is equivalent to predictability (or the lack thereof) of the demand for money (since in equilibrium real money demand is simply ). Either way, this unpredictability made policy-makers at the Federal Reserve rely less on the money supply in steering the U.S. economy. Instead, the policy focus has shifted to interest rates such as the fed funds rate.