America is just weeks away from a mighty economic shock

Five years ago, when the pandemic shut down the global economy, frazzled economists turned to novel measures, such as mobility data and restaurant bookings, to track the closure in real time. Now the world is desperate to assess the damage caused by Donald Trump's swingeing tariffs on Chinese imports, and pundits are again using innovative techniques. Their findings suggest the world's biggest economy is not reeling yet. But trouble is coming. Even before the implementation of many of the tariffs, on April 9, polling suggested American consumers and businesses were already worried. According to a survey by the Dallas branch…