The 56 US states and territories we track report their total test results in three main ways: by specimens tested, by people tested, and by “test encounters,” a unit which usually counts unique people tested per day.
In the early months of the pandemic, many of the jurisdictions we track reported positive and negative tests, but not total tests. To arrive at a total tests number for each jurisdiction, we added together the positive and negative numbers from states and territories. (This method usually produced a total tests number reported in people.) COVID-19 data reporting has significantly improved since the spring of 2020, and this method is no longer required.
As we make the transition from using computed total test numbers to direct reporting of the total test numbers states publish, we are publishing total test numbers in all available units for each state and territory on our website, and in separate fields in our API. Where we must choose a unit for total tests reporting, we are prioritizing units of test encounters and specimens above people—a change which we believe will provide the most useful measure of each jurisdiction’s testing capacity. For more information on how and why we are changing our reporting methods, please see “Counting COVID-19 Tests: How States Do It, How We Do It, and What’s Changing.”
This page will serve as a central reference where our API and website users can easily see which states are reporting total tests in each unit and how this information is reflected on our site and in the API.
On our website, we report all the total tests metrics that each state or territory provides, so many states will have two “total tests” numbers, each labeled by the unit in which they’re reported.
In the “New tests” chart on each state page, we require at least 150 days of historical data to visualize in the chart. For states that offer multiple total tests metrics with 150 days of historical data, we use, in order of most to least preferred, tests reported in testing encounters, tests reported in specimens, or tests reported in people. Otherwise, we default to “total test results,” which sums the state’s positive and negative figures.
The total tests metric we visualize in each state’s chart is labeled on the chart itself, and also listed below.
In our API, we offer multiple total test fields, which you can learn about on our Data Definitions page. These include three fields with different units (specimens, people, and encounters) that draw direct totals figures from states whenever they are available, and our original total tests field, which is still calculated for most jurisdictions by adding together that jurisdiction’s positive and negative results (totalTestResults).
We are gradually switching our totalTestResults field to draw totals directly from the test encounters, specimens, and people field, in that priority order. We only switch to non-calculated, directly reported total tests for a state or territory when that state or territory has provided a time-series stretching back to March. So far, we have switched Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, the District of Columbia, Florida, Georgia, Hawaii, Idaho, Illinois, Indiana, Kentucky, Maryland, Maine, Massachusetts, Michigan, Minnesota, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Mexico, New York, North Carolina, North Dakota, Ohio, Oregon, Pennsylvania, Rhode Island, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, and Wyoming. Since September 17, 2020, these changes have been reflected in the national totalTestResults field.