New statewide testing metric and methodology updates announced

  • Mon Aug 31st, 2020 2:23pm
  • News

Submitted by the Washington State Department of Health

The Washington State Department of Health is making changes to the way we process and report testing data statewide, in an effort to account for the true volume of tests being done and to better benchmark our progress.

Changes made Aug. 25:

Total tests – The DOH will now report the total number of tests instead of the total individuals who were tested. This is a change from the old approach, which counted just one test per person, even if someone was tested more than once. With this new change, every test is counted, and the new data will improve our understanding of the testing situation as it now fully reflects the actual testing volume. This change aligns with other states’ methods as well as the Centers for Disease Control and Prevention.

Percent positive – The percent no longer be based on the percentage of unique individuals who test positive to the percentage of positive tests. While the data will change, and the DOH anticipates the percent positive will decrease somewhat because it is now accounting for total tests, the dashboard visualizations will stay the same.

Daily Testing Rate– The DOH added this metric to the Risk Assessment dashboard. This will help the DOH to understand the per capita testing levels in the state and by county. The new measure allows easy comparisons of counties and other locations allowing a better benchmark the state’s progress. It is calculated by dividing the average number of molecular tests performed over the past week by the population in the county or state and then multiplying by 100,000. The DOH will not include any targets at this time, but that could change. This metric will replace the current, “Individuals tested per new case” on the risk assessment dashboard (an additional way of expressing the “percent positive” metric).