To better identify both optimistic propaganda and useless pessimism, it’s important to see the limitations of the data we have before us.

Let’s start with the health statistics. A quick glance at available data in America will show coronavirus infection rates rising at a terrifying clip. In the U.S., the number of total confirmed cases is doubling every three days—quicker than in Italy, France, or the U.K.

But we have to be careful about drawing hard conclusions from that one statistic. Confirmed cases are a function of confirmed tests. After a tragically late start, U.S. testing capacity has doubled in the past week. Is the U.S. currently experiencing rapid growth in coronavirus cases, or rapid growth in coronavirus testing, or both? The answer should sound familiar: We don’t know yet, and it will be a while before we do.

Other metrics used to gauge the scale of the outbreak, such as hospitalizations and deaths, have their own limitations. Not all states are reporting hospitalizations, and once hospitals are full, additional cases might not show up in reported figures. Death statistics are also a function of case-by-case diagnosis and cause-of-death methodology. Many deaths due to COVID-19 may have been—and many more may continue to be—misdiagnosed as the result of pneumonia or another respiratory ailment.

With time and increased testing, the state of this outbreak will come into focus. But leaders should be humble, and citizens must be patient, about the fact that no single metric is gospel right now. Even many health statistics taken together can offer at best an incomplete picture of the scope of the crisis.

The economic front is equally murky. Predictions among investment banks for the second-quarter change in GDP range from a 12 percent decline (Bank of America) to a 30 percent decline (Morgan Stanley). That’s not a sign of economists having an informed debate. It’s a sign that economists have no idea what’s going on.

And how could they? This sudden-onset recession has no precedent in American history. Our economic tools are not designed to quickly and accurately measure this kind of abrupt devastation.

One example is the official unemployment rate. The Bureau of Labor Statistics will publish on April 3 its first estimate of March unemployment. You might expect that this official report will finally offer clarity on the economic picture in the U.S.

Don’t get your hopes up. According to the Cornell economist Erica Groshen, the report will tell us practically nothing about what happened in the second half of March. “The initial BLS surveys are conducted the week of the 12th of each month,” she told me. “So in April we will get an estimate of the unemployment rate from the week of March 12.”

March 12 was the Thursday before many states and cities announced, the following Sunday, that they would be closing all restaurants and bars. The economy in the first two weeks of March was entirely different from the economy in these past two weeks of March. We won’t have an accurate picture of the March unemployment rate until the BLS releases its next revision, in May, an eternity in pandemic timekeeping.