President Donald Trump has repeatedly touted the fact that the United States has tested more people for COVID-19, the disease caused by the novel coronavirus, than any other nation in the world. In pure numbers, this is true: As of July 7, 2020, roughly 36 million people across the country have been tested for the virus. This dwarfs the total testing number of any other nation (India is currently #2 at about 10 million tests). But, considering the size of the U.S. and the scale of its outbreak, 36 million is far less impressive; that figure means about 11% of the population has been tested—or about the acceptance rate to Cornell University.
COVID-19 testing should not be so competitive. The Harvard Global Health Institute, in collaboration with NPR, on June 23 published estimates for how many daily tests the U.S. should conduct to accurately determine the number of infected Americans, as well as close contacts who may have been exposed. They concluded at least 4.3 million tests per day are needed, a number based on modeling by data scientist Youyang Gu—whose work is cited by the Centers for Disease Control and Prevention (CDC)—as well as from other researchers and journalists who consider his work a comprehensive predictor of COVID-19 rates over the next few months as it takes into account policy changes, such as the reopening of business in many states.
The Harvard team's estimates have jumped from two earlier analyses done in mid-April and early May, which placed the country's need at 500,000–700,000 tests per day and 900,000 tests per day, respectively. The significant jump may be attributed to rising outbreaks in the south and west of the country, brought on by reopening policies in many states. Still, testing more than 4 million Americans each day is only the first step to safely contain the pandemic and reopen the country; other measures—such as testing equitably across vulnerable populations, tracing the friends and family members of those infected, and ensuring that people with severe cases have access to treatment—are similarly crucial. These tests should also not be evenly distributed across the country, as every state has different needs based on the size of its outbreak and its lockdown policies (or lack thereof). Gu's forecasts take these differences into account, as do the Harvard team's target estimates for each region.
Stacker compared the Harvard team's state-specific targets to the actual testing conducted in every state over the past week (June 30 to July 7) to determine whether states have completed enough tests in order to safely reopen. Actual testing data are sourced from the COVID Tracking Project, an independent volunteer effort housed at The Atlantic which compiles daily figures from health department websites and press releases. All 50 states and Washington D.C. are ranked here according to what percentages of their mitigation and suppression targets have been met. These targets are defined as follows:
Mitigation target: The number of tests that, if administered throughout the state, would reduce the spread of the virus through broad investigation of symptomatic people and basic contact tracing; and
Suppression target: The number of tests needed to keep a state's new case levels at zero.
It is key to note that every state health department varies in how it reports testing results as well as other disease metrics. Some states, such as California, are reporting the number of lab specimens tested for COVID-19, while others like New York are reporting the number of people tested. As the same person may be tested multiple times or multiple specimens may be tested per person, this discrepancy in reporting makes it difficult to compare sheer testing numbers across states.
Still, we can compare a state's testing numbers to its positive rate, as we are doing here with a metric called the "positive test ratio" or "test-positivity rate," defined as the share of COVID-19 tests that have returned positive results. The World Health Organization recommends a positive test ratio of 10% as an indicator that a region is testing enough people to accurately measure the scale of its outbreak. A higher positive test ratio indicates that only symptomatic individuals are being tested and the outbreak is not yet under control.
Editor's Note: Betsy Ladyzhets, a research associate at Stacker who worked on this story, volunteers for the COVID-19 Tracking Project.
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