The Times has identified the following reporting anomalies

 

The Times has identified the following reporting anomalies or methodology changes in the data:

• May 31, 2021: The daily count is artificially low because many states and local jurisdictions did not announce new data on Memorial Day.
• May 27, 2021: Maryland added many backlogged deaths.
• May 26, 2021: Oklahoma added many backlogged deaths.
• April 26, 2021: New Jersey removed more than 10,000 duplicate cases.
• April 7, 2021: Oklahoma added many deaths from previous months.
• March 8, 2021: Missouri began reporting probable cases identified through antigen testing.
• March 2, 2021: Ohio removed many deaths after changing its methodology, resulting in an artificially low daily count.
• Feb. 13, 2021: Ohio added many backlogged deaths from recent months.
• Feb. 12, 2021: Ohio added many backlogged deaths from recent months.
• Feb. 11, 2021: Ohio added many backlogged deaths from recent months.
• Feb. 4, 2021: Indiana announced about 1,500 deaths from previous months after reconciling records.
• Jan. 2, 2021: The daily count is artificially high because many states and local jurisdictions announced backlogged data after not announcing new data on New Year's Day.
• Jan. 1, 2021: The daily count is artificially low because many states and local jurisdictions did not announce new data on New Year's Day.
• Dec. 25, 2020: The daily count is artificially low because many states and local jurisdictions did not announce new data on Christmas.
• Dec. 11, 2020: Texas began reporting probable cases, resulting in a one-day increase of about 44,000 cases.
• Nov. 26, 2020: Cases and deaths were lower because 14 states reported no new data, and six states had only incomplete data from select counties.
• Nov. 4, 2020: Georgia began reporting probable deaths, causing a one-day increase.
• Sept. 21, 2020: Texas added thousands of undated, backlogged cases, causing a spike in the state and national data.
• July 27, 2020: Texas began reporting deaths based on death certificates, causing a one-day increase.
• June 30, 2020: New York City added a backlog of deaths from unspecified dates.
• June 25, 2020: New Jersey began reporting probable deaths, including those from earlier in the pandemic, causing a jump in the number of total deaths.

• To see a detailed list of all reporting anomalies, visit the individual state pages listed at the bottom of this page.

Confirmed cases and deaths, which are widely considered to be an undercount of the true toll, are counts of individuals whose coronavirus infections were confirmed by a molecular laboratory test. Probable cases and deaths count individuals who meet criteria for other types of testing, symptoms and exposure, as developed by national and local governments.

Governments often revise data or report a single-day large increase in cases or deaths from unspecified days without historical revisions, which can cause an irregular pattern in the daily reported figures. The Times is excluding these anomalies from seven-day averages when possible.