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COVID-19 data definitions change frequently across the 56 jurisdictions we track, so we must sometimes update our data definitions to reflect the realities we find in the data. As we track additional data points and adjust the definition of current fields to accommodate changes from states and territories, we will update the definitions here. We will also publish update notices on the blog for major additions and changes. If you think you’ve spotted an error in the definitions or their use in our compiled data, please let us know.

Cases

Cases (confirmed plus probable)

API field name: positive

Total number of confirmed plus probable cases of COVID-19 reported by the state or territory, ideally per the August 5, 2020 CSTE case definition. Some states are following the older April 5th, 2020 CSTE case definition or using their own custom definitions. Not all states and territories report probable cases. If a state is not reporting probable cases, this field will just represent confirmed cases.

New cases

API field name: positiveIncrease

The daily increase in API field positive, which measures Cases (confirmed plus probable) calculated based on the previous day’s value.

Probable Cases

API field name: probableCases

Total number of probable cases of COVID-19 as reported by the state or territory, ideally per the August 5, 2020 CSTE case definition. By this definition, a probable case is someone who tests positive via antigen without a positive PCR or other approved nucleic acid amplification test (NAAT), someone with clinical and epidemiological evidence of COVID-19 infection with no confirmatory laboratory testing performed for SARS-CoV-2, or someone with COVID-19 listed on their death certificate with no confirmatory laboratory testing performed for SARS-CoV-2. Some states are following the older April 5th, 2020 CSTE case definition or using their own custom definitions.

PCR tests

Confirmed Cases or Positive PCR tests (people)

API field name: positiveCasesViral

Total number of unique people with a positive PCR or other approved nucleic acid amplification test (NAAT), as reported by the state or territory. This is equivalent to a confirmed case as per the CSTE case definitions of August 5th, 2020 and April 5th, 2020. If we discover a jurisdiction is labeling cases as confirmed using other evidence (e.g. positive antigen tests), we will annotate that state or territory’s data accordingly.

Negative PCR tests (people)

API field name: negative

Total number of unique people with a completed PCR test that returns negative. For states / territories that do not report this number directly, we compute it using one of several methods, depending on which data points the state provides. Due to complex reporting procedures, this number might be mixing units and therefore, at best, it should only be considered an estimate of the number of people with a completed PCR test that return negative.

Negative PCR tests (specimens)

API field name: negativeTestsViral

Total number of completed PCR tests (or specimens tested) that return negative as reported by the state or territory. For states/territories that do not report this number directly, we compute it using one of several methods, depending on which data points the state provides. If we discover that a jurisdiction is including antigen tests in this metric, we will annotate that state or territory’s data accordingly.

Pending

API field name: pending

Total number of viral tests that have not been completed as reported by the state or territory.

Positive PCR tests (specimens)

API field name: positiveTestsViral

Total number of completed PCR tests (or specimens tested) that return positive as reported by the state or territory. If we discover that a jurisdiction is including antigen tests in this metric, we will annotate that state or territory’s data accordingly.

Total PCR tests (people)

API field name: totalTestsPeopleViral

Total number of unique people tested at least once via PCR testing, as reported by the state or territory. The count for this metric is incremented up only the first time an individual person is tested and their result is reported. Future tests of the same person will not be added to this count.

In the case where the state only provides negative cases, this field is calculated as the summation of people who tested positive (“Positive Cases (People”) and the number of people who tested negative (“Negative (People or Cases)”). If we discover that a jurisdiction is including antigen tests in this metric, we will annotate that state or territory’s data accordingly.

Total PCR tests (specimens)

API field name: totalTestsViral

Total number of PCR tests (or specimens tested) as reported by the state or territory. The count for this metric is incremented up each time a specimen is tested and the result is reported. If we discover that a jurisdiction is including antigen tests in this metric, we will annotate that state or territory’s data accordingly. For states with ambiguous annotations, we have assigned their total tests to this category; these states and territories are identified in the new API field covidTrackingProjectPreferredTotalTestUnits as having “Unclear units.”

Total PCR tests (test encounters)

API field name: totalTestEncountersViral

Total number of people tested per day via PCR testing as reported by the state or territory. The count for this metric is incremented up by one for each day on which an individual person is tested, no matter how many specimens are collected from that person on that day. If an individual person is tested twice a day on three different days, this count will increment up by three. If we discover that a jurisdiction is including antigen tests in this metric, we will annotate that state or territory’s data accordingly.

Antibody tests

Negative antibody tests (people)

API field name: negativeTestsPeopleAntibody

The total number of unique people with completed antibody tests that return negative as reported by the state or territory.

Negative antibody tests (specimens)

API field name: negativeTestsAntibody

The total number of completed antibody tests that return negative as reported by the state or territory.

Positive antibody tests (people)

API field name: positiveTestsPeopleAntibody

The total number of unique people with completed antibody tests that return positive as reported by the state or territory.

Positive antibody tests (specimens)

API field name: positiveTestsAntibody

Total number of completed antibody tests that return positive as reported by the state or territory.

Total antibody tests (people)

API field name: totalTestsPeopleAntibody

The total number of unique people who have been tested at least once via antibody testing as reported by the state or territory.

Total antibody tests (specimens)

API field name: totalTestsAntibody

Total number of completed antibody tests as reported by the state or territory.

Antigen tests

Positive antigen tests (people)

API field name: positiveTestsPeopleAntigen

Total number of unique people with a completed antigen test that returned positive as reported by the state or territory.

Positive antigen tests (specimens)

API field name: positiveTestsAntigen

Total number of completed antigen tests that return positive as reported by the state or territory.

Total antigen tests (people)

API field name: totalTestsPeopleAntigen

Total number of unique people who have been tested at least once via antigen testing, as reported by the state or territory.

Total antigen tests (specimens)

API field name: totalTestsAntigen

Total number of completed antigen tests, as reported by the state or territory.

Hospitalization

Cumulative hospitalized/Ever hospitalized

API field name: hospitalizedCumulative

Total number of individuals who have ever been hospitalized with COVID-19. Definitions vary by state / territory. Where possible, we report hospitalizations with confirmed or probable COVID-19 cases per the expanded CSTE case definition of April 5th, 2020 approved by the CDC.

Cumulative in ICU/Ever in ICU

API field name: inIcuCumulative

Total number of individuals who have ever been hospitalized in the Intensive Care Unit with COVID-19. Definitions vary by state / territory. Where possible, we report patients in the ICU with confirmed or probable COVID-19 cases per the expanded CSTE case definition of April 5th, 2020 approved by the CDC.

Cumulative on ventilator/Ever on ventilator

API field name: onVentilatorCumulative

Total number of individuals who have ever been hospitalized under advanced ventilation with COVID-19. Definitions vary by state / territory. Where possible, we report patients on ventilation with confirmed or probable COVID-19 cases per the expanded CSTE case definition of April 5th, 2020 approved by the CDC.

Currently hospitalized/Now hospitalized

API field name: hospitalizedCurrently

Individuals who are currently hospitalized with COVID-19. Definitions vary by state / territory. Where possible, we report hospitalizations with confirmed or probable COVID-19 cases per the expanded CSTE case definition of April 5th, 2020 approved by the CDC.

Currently in ICU/Now in ICU

API field name: inIcuCurrently

Individuals who are currently hospitalized in the Intensive Care Unit with COVID-19. Definitions vary by state / territory. Where possible, we report patients in the ICU with confirmed or probable COVID-19 cases per the expanded CSTE case definition of April 5th, 2020 approved by the CDC.

Currently on ventilator/Now on ventilator

API field name: onVentilatorCurrently

Individuals who are currently hospitalized under advanced ventilation with COVID-19. Definitions vary by state / territory. Where possible, we report patients on ventilation with confirmed or probable COVID-19 cases per the expanded CSTE case definition of April 5th, 2020 approved by the CDC.

New total hospitalizations

API field name: hospitalizedIncrease

Daily increase in hospitalizedCumulative, calculated from the previous day’s value.

Outcomes

Deaths (confirmed and probable)

API field name: death

Total fatalities with confirmed OR probable COVID-19 case diagnosis (per the expanded CSTE case definition of April 5th, 2020 approved by the CDC). In states where the information is available, it only tracks fatalities with confirmed OR probable COVID-19 case diagnosis where on the death certificate, COVID-19 is listed as an underlying cause of death according to WHO guidelines.

Deaths (confirmed)

API field name: deathConfirmed

Total fatalities with confirmed COVID-19 case diagnosis (per the expanded CSTE case definition of April 5th, 2020 approved by the CDC). In states where the information is available, it only tracks fatalities with confirmed COVID-19 case diagnosis where on the death certificate, COVID-19 is listed as an underlying cause of death according to WHO guidelines.

Deaths (probable)

API field name: deathProbable

Total fatalities with probable COVID-19 case diagnosis (per the expanded CSTE case definition of April 5th, 2020 approved by the CDC). In states where the information is available, it only tracks fatalities with probable COVID-19 case diagnosis where on the death certificate, COVID-19 is listed as an underlying cause of death according to WHO guidelines.

New deaths

API field name: deathIncrease

Daily increase in death, calculated from the previous day’s value.

Recovered

API field name: recovered

Total number of people that are identified as recovered from COVID-19. States provide very disparate definitions on what constitutes a “recovered” COVID-19 case. Types of “recovered” cases include those who are discharged from hospitals, released from isolation after meeting CDC guidance on symptoms cessation, or those who have not been identified as fatalities after a number of days (30 or more) post disease onset. Specifics vary for each state or territory.

State metadata

COVID Tracking Project preferred total test field

API field name: covidTrackingProjectPreferredTotalTestField

Locator field that explains which API fields The COVID Tracking Project prefers for each state’s “New tests” chart and on the state’s history page on our website. Selects from the following options in order of priority: totalTestEncountersViral, totalTestsViral, totalTestsPeopleViral, or—where those units are all missing a sufficient time series—totalTestResults.

COVID Tracking Project preferred total test units

API field name: covidTrackingProjectPreferredTotalTestUnits

Label indicating which units The COVID Tracking Project prefers for each state’s “New tests” chart and on the state’s history page on our website. Selects from the following options in order of priority: test encounters, specimens, people, or—where those units are all missing a sufficent time series—negatives plus positives.

Data Quality Grade

API field name: dataQualityGrade

The COVID Tracking Project grade of the completeness of the data reporting by a state. See our State Grades page and our spreadsheet of grade factors for more information.

Date

API field name: date

Date on which data was collected by The COVID Tracking Project.

Last Update (ET)

API field name: lastUpdateEt

Date and time in Eastern time the state or territory last updated the data.

New tests

API field name: totalTestResultsIncrease

Daily increase in totalTestResults, calculated from the previous day’s value. This calculation includes all the caveats associated with Total tests/totalTestResults, and we recommend against using it at the state/territory level.

State (or territory)

API field name: state

Two-letter abbreviation for the state or territory.

States

API field name: states

Only available in national records. The number of states and territories included in the US dataset for this day.

Total test results

API field name: totalTestResults

At the national level, this metric is a summary statistic which—because it sums figures from states reporting tests in test encounters with those reporting tests in specimens and in people—is an aggregate calculation of heterogeneous figures. Therefore, it should be contextualized as, at best, an estimate of national testing performance.

In most states, the totalTestResults field is currently computed by adding positive and negative values because, historically, some states do not report totals, and to work around different reporting cadences for cases and tests. In Colorado, Delaware, the District of Columbia, Florida, Hawaii, Minnesota, Nevada, New York, North Dakota, Rhode Island, Virginia, Washington, and Wisconsin, where reliable testing encounters figures are available with a complete time series, we directly report those figures in this field. In Alabama, Alaska, Arkansas, Georgia, Indiana, Kentucky, Maryland, Massachusetts, Missouri, Nebraska, New Hampshire, Utah, and Vermont, where reliable specimens figures are available with a complete time series, we directly report those figures in this field. In Arizona, Idaho, and South Dakota, where reliable unique people figures are available with a complete time series, we directly report those figures in this field. We are in the process of switching all states over to use directly reported total figures, using a policy of preferring testing encounters, specimens, and people, in that order.