This is a weighted average of short-term interest rates, corporate-bond yields, share prices and the trade-weighted dollar, with the weights derived from the Fed's model.

ECONOMIST: Is monetary policy less effective these days?

For example, the Goldman Sachs monetary-conditions index (based on a weighted average of short-and long-term interest rates and the trade-weighted exchange rate) suggests that America's monetary policy is currently at its tightest since 1989, largely reflecting the strong dollar.

ECONOMIST: The stockmarket economy