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For months, we have been collecting COVID-19 data, scrutinizing publicly available data definitions, and engaging in frequent conversations with jurisdictions to understand the data they share.

During this process, we have focused on three aspects of COVID-19 data reporting: 1) how the state defines and reports key metrics, such as testing data, cases, hospitalizations, and deaths, 2) how the state presents information about COVID-19 in long-term-care facilities, and 3) how the state reports race and ethnicity data.

Our assessment below reflects both the thoroughness of California’s reporting and the completeness and clarity of their data descriptions. We hope this work will not only help our data users to better grasp the limitations of these numbers but also might help health officials to understand the differences in data reporting across jurisdictions.

We require data definitions to be accessible from a state’s data pages and presented in a location where it is clear they will be maintained. Examples include data definition documents, data FAQs, dashboard footnotes, or definitions appearing daily in press releases.

Last updated March 2, 2021

State-level metrics

Serious issues exist:

  • does not have a clear full definition of cases
  • does not provide a breakdown of confirmed and probable cases
  • does not publish what test types are included in their main testing metric
  • does not provide a testing metric clearly including only viral RNA tests
  • does not regularly provide antigen total test counts
  • does not regularly provide antigen positive test counts
  • does not regularly provide total tests in terms of unique people tested
  • does not provide numbers for patients currently on ventilators with COVID-19
  • does not regularly provide a cumulative number of patients hospitalized with COVID-19

Race and Ethnicity

Few issues exist:

  • does not report race / ethnicity data for hospitalizations
  • reports race data for 77% of cases and 98% of deaths

Long-Term Care

Few issues exist:

  • California's skilled nursing facilities do not include deaths of residents that occurred in a different location 14-days after a resident is transferred to another setting, such as a hospital. This may result in an undercount of long-term-care deaths. Interpret California deaths with caution.
  • does not provide information about facilities with open and closed outbreaks, or date of last case