A model based on Okun’s law can help policy-makers predict how early estimates of GDP might be revised during a crisis, a paper from the Federal Reserve Bank of San Francisco finds.

Early estimates of GDP are often considerably revised in periods of stress as more complete information comes available, the authors say.

Òscar Jordà and his co-authors outline a three-pronged strategy to help policy-makers get a better sense of GDP growth in real time by predicting potential revisions. They use