It's a mad scramble for the best data: Economists are grappling with ways to gauge the real-time impact of the coronavirus on the world economy, even as the outbreak continues to confound forecasters.

Store closures, flight-tracking websites, factory shutdowns and the latest numbers on infections and fatalities are just some of the high-frequency data points economists are scouring for clues on the hit to growth.

"To track the impact of the virus on the global economy, we have had to look at indicators I have never looked at before in my 25 years of doing macroeconomic forecasting," said Torsten Slok, chief economist for Deutsche Bank AG.