1 # Cases and Deaths Rolling Averages and Anomalous Days
3 The data in these files is a different version of the data in our main U.S. cases and deaths [files](https://github.com/nytimes/covid-19-data). Instead of cumulative totals, each file contains the daily number of new cases and deaths, the seven-day rolling average and the seven-day rolling average per 100,000 residents.
5 This data was reported by dozens of journalists at The Times, drawing from a patchwork of county, state and national government sources. The ever-evolving nature of the coronavirus pandemic meant that the way these officials reported their data was not always consistent.
7 In compiling data, we chose to prioritize the accuracy of our cumulative case counts. Because of that, the number of new daily cases may at times appear anomalous because it is derived from the difference in cumulative cases from one day to another.
9 In creating our rolling averages, we’ve drawn on our experience reporting coronavirus data since early 2020. Using that editorial judgment and expertise, we elected to exclude certain data points from the calculation of these averages because they would skew county, state or national trends in the data. These instances are listed, as is our best understanding of the reason for the data anomaly.
11 All the methodology noted in our description of the main cases and deaths data continues to apply here.
15 The fields have the following definitions:
17 * **geoid**: A unique geographic identifier for each place. For counties and states, the final five digits are the same as the FIPS code when possible. In instances where we have assigned a non-standard identifier, the geoid will end in `99[0-9]`.
18 * **cases**: The number of new cases of Covid-19 reported that day, including both confirmed and probable.
19 * **cases_avg**: The average number of new cases reported that day and the six days prior. In other words, the seven-day trailing average. See the methodology section for a more detailed discussion of edge cases in how this is calculated.
20 * **cases_avg_per_100k**: The `cases_avg` per 100,000 people.
21 * **deaths**: The total number of new deaths from Covid-19 reported that day, including both confirmed and probable.
22 * **deaths_avg**: The average number of new deaths reported that day and the six days prior. In other words, the seven-day trailing average.
23 * **deaths_avg_per_100k**: The `deaths_avg` per 100,000 people.
26 ### U.S. National-Level Data
28 The daily number of newly reported cases and deaths nationwide, including all states, U.S. territories and the District of Columbia, can be found in the [us.csv](us.csv) file. ([Raw CSV file here.](https://raw.githubusercontent.com/nytimes/covid-19-data/master/rolling-averages/us.csv))
31 date,geoid,cases,cases_avg,cases_avg_per_100k,deaths,deaths_avg,deaths_avg_per_100k
32 2020-01-21,USA,1,0.14,0,0,0,0
38 State-level data can be found in the [states.csv](us-states.csv) file. ([Raw CSV file here.](https://raw.githubusercontent.com/nytimes/covid-19-data/master/rolling-averages/us-states.csv))
41 date,geoid,state,cases,cases_avg,cases_avg_per_100k,deaths,deaths_avg,deaths_avg_per_100k
42 2020-01-21,USA-53,Washington,1,0.14,0,0,0,0
48 County-level data can be found in the [counties.csv](us-counties.csv) file. ([Raw CSV file here.](https://raw.githubusercontent.com/nytimes/covid-19-data/master/rolling-averages/us-counties.csv))
51 date,geoid,county,state,cases,cases_avg,cases_avg_per_100k,deaths,deaths_avg,deaths_avg_per_100k
52 2020-01-21,USA-53061,Snohomish,Washington,1,0.14,0.02,0,0,0
56 Of note, this counties file is too large to be opened in Excel. There is also a file [us-counties-recent.csv](us-counties-recent.csv) that is smaller and contains data on counties for just the last 30 days and can be opened in Excel. ([Raw CSV file here.](https://raw.githubusercontent.com/nytimes/covid-19-data/master/rolling-averages/us-counties-recent.csv))
60 The list of anomalous days is in the [anomalies.csv](anomalies.csv) file. ([Raw CSV file here.](https://raw.githubusercontent.com/nytimes/covid-19-data/master/rolling-averages/anomalies.csv))
63 date,end_date,county,state,geoid,type,omit_from_rolling_average,omit_from_rolling_average_on_subgeographies,description
64 2020-04-06,,New York City,New York,USA-36998,deaths,,,The Times began using deaths reported by the New York State Health Department instead of the city's health department.
68 The fields have the following definitions:
70 * **date**: The date to which the anomaly applies.
71 * **end_date**: For anomalies that span multiple days, the last day to which it applies. Otherwise, left blank.
72 * **geoid**: A unique geographic identifier for each place. Use this to match against the file of rolling averages.
73 * **type**: Whether the anomaly applies to the data on cases, deaths or both.
74 * **omit_from_rolling_average**: This will be `yes` if the data for that day is excluded from the calculation of rolling averages. Otherwise, left blank.
75 * **omit_from_rolling_average_on_subgeographies**: This will be `yes` if the data for that day is excluded from the calculation of rolling averages, for all subgeographies, i.e. the counties within a state. Otherwise, left blank.
76 * **description**: A note explaining the cause for the anomaly, based on data reporting and/or communication with local officials. These explanations appear at the bottom of the geography tracking pages.
79 ### Anomalies Methodology
81 The list of anomalies published here is curated and maintained based on our daily review of newly reported case and death counts published each day, and verified by public statements published by health departments either publicly or via press releases, or our own additional reporting and research. It is neither a complete list of all anomalies with Covid data, nor based on any statistical outlier detection.
83 Identified anomalies are often because of officials making revisions to improve the overall quality of the data they have released. Many small anomalies due to backlogs of cases or minor revisions of previously announced numbers are not included here, particularly at the county level. There are no listed anomalies from very early in the pandemic. When deciding whether to list an anomaly, we judge whether a member of the public would need that note to understand and put in context that day’s case or death count.
85 When deciding whether to exclude an anomaly from our rolling averages, we use our best judgment of whether including the day in the rolling average would significantly distort the overall trend appearing in the data. Since data fluctuations are common and agencies vary in their typical reporting rhythms, we have found it is not beneficial to use a completely objective standard, and we err toward not removing data from the rolling averages. Factors we consider include: the proportion of anomalous cases or deaths in the daily total, whether the information is relevant to recent trends, and how much delay or variation is typical for a particular data source.
87 We sometimes remove a day’s numbers from the rolling average at the state level, but not at the county level or vice versa, because county- and state-level data can come from different sources, or a state may provide a more detailed explanation of cases at the state level than it does at the county level.
89 Population data used to calculate per capita figures comes from the U.S. Census Bureau 2019 population estimate.
92 ## License and Attribution
94 This data is licensed under the same terms as our [Coronavirus Data in the United States data](https://github.com/nytimes/covid-19-data). In general, we are making this data publicly available for broad, noncommercial public use, including by medical and public health researchers, policymakers, analysts and local news media.
96 If you use this data, you must attribute it to “The New York Times” in any publication. If you would like a more expanded description of the data, you could say, “Data from The New York Times, based on reports from state and local health agencies.”
98 For papers following APA format, we recommend the following citation: "The New York Times. (2021). Coronavirus (Covid-19) Data in the United States. Retrieved [Insert Date Here], from https://github.com/nytimes/covid-19-data."
100 If you use it in an online presentation, we would appreciate it if you would link to our U.S. tracking page at [https://www.nytimes.com/interactive/2020/us/coronavirus-us-cases.html](https://www.nytimes.com/interactive/2020/us/coronavirus-us-cases.html).
102 If you use this data, please let us know at covid-data@nytimes.com.
104 See our [LICENSE](https://github.com/nytimes/covid-19-data/blob/master/LICENSE) for the full terms of use for this data.
108 If you have questions about the data or licensing conditions, please contact us at:
110 covid-data@nytimes.com
114 [The list of contributors is the same as the list for the primary Coronavirus Data in the United States data](https://github.com/nytimes/covid-19-data)