COVID-19 Alert

Methods for the Roadmap to Recovery Metrics

Effective January 11, 2021, the State of Washington launched Healthy Washington — Roadmap to Recovery which uses a regional approach for the phased recovery plan. This report describes the four metrics and corresponding thresholds for the Roadmap to Recovery. More information on the phase recovery plan and reopening guidelines are available on this website.

The four metrics provide an overview of current COVID-19 trends and healthcare system readiness in each region. The four metrics are:

  1. Trend in case rate - Trend in 14-day rate of new COVID-19 cases per 100K population;
  2. Trend in hospital admissions rate - Trend in 14-day rate of new COVID-19 hospital admissions per 100K population;
  3. Percent ICU Occupancy - Average 7-day percent occupancy of ICU staffed beds; and
  4. Percent Positivity - 7-day percent positive of COVID-19

Methods

Regions
The regions used in this report are largely based on the Emergency Medical Services (EMS) regions used for evaluating available healthcare services given the concern for COVID-19’s potential impact on the healthcare system. Regions are defined as illustrated in the map below.

map - Copy

 

Population
The population data used to calculate the case and hospital admission rates is the single year 2019 intercensal estimate from the Washington State Office of Financial Management, found here.

Data sources
There are three data sources for these metrics: the Washington Disease Reporting System (WDRS), WA HEALTH, and the WA Department of Health (DOH) negative labs dataset. These data sources are all dynamic. They are updated daily as we receive more complete information and they change over time as we learn more

We select time frames to maximize timeliness and completeness of the data, report data based on 7- or 14-day periods from Sunday-Saturday and implement a standardized process for releasing the report on a regular schedule. Timeliness and completeness differ by data source. For this report, we consider the most recent 14 days of data from WDRS to be incomplete. It takes up to 12 days from specimen collection date for DOH to receive 90% of reported cases and there is a 2-day delay in preparing the report. We consider the most recent 17 days of data from the negative lab's dataset to be incomplete and there is a 2-day delay in preparing the report. We consider the most recent 6 days of data from WA HEALTH to be incomplete as it takes up to 4 days for DOH to receive and conduct quality checks on the data and there is 2-day delay in preparing the report.

This results in different time frames used for the metrics because they come from these different data sources. Time delays for obtaining complete data from all data sources will be reviewed regularly and updated whenever possible.

Metrics
Trend in case rate
The Trend in 14-day rate of new COVID-19 cases per 100K population metric describes whether virus transmission is increasing, decreasing, or staying the same (referred to here as “flattening”). A case is defined as an individual with a molecular or antigen test that is positive for COVID-19. Cases are assigned to the date a specimen was collected for testing, called the specimen collection date.

This metric is calculated by dividing the number of cases with a specimen collection date in a 14-day period by the population in the region and multiplying by 100,000. The percent change is calculated by subtracting the rate during the most recent time period from the preceding time period, dividing by the rate in the preceding time period, and multiplying by 100. The direction of the trend is defined by thresholds. The thresholds for this metric are:

  • Decrease: -10% or more
  • Flat: between 0% to less than -10%
  • Increase: More than 0%

Data from WDRS are used for this metric. Metrics are calculated using the most recent complete data for two Sunday–Saturday weeks.

Trend in hospital admission rate
The Trend in 14-day rate of new COVID-19 hospital admissions per 100K population metric describes the impact on healthcare systems and whether the number of hospital admissions is increasing, decreasing, or flattening. A hospital admission is defined as an individual with confirmed COVID-19 infection who was admitted to the hospital. A hospital admission is assigned to the region of the hospital, not the region in which the individual lives. About 90% or more of Washington residents with COVID-19 in November 2020 were determined to reside in the same region as the hospital.

This metric is calculated by dividing the number of COVID-19 hospital admissions with an admission date in a 14-day period by the population in the region and multiplying by 100,000. The percent change is calculated by subtracting the rate during the most recent time period from the preceding time period, dividing by the rate in the preceding time period, and multiplying by 100. The direction of the trend is defined by thresholds. The thresholds for this metric are:

  • Decrease: -10% or more
  • Flat: between 0% to less than -10%
  • Increase: More than 0%

Data from WA HEALTH are used for this metric. Metrics are calculated using the most recent complete data for two Sunday–Saturday weeks.

Percent ICU occupancy
The Average 7-day percent occupancy of ICU staffed beds metric describes the capacity of the healthcare system to respond to the pandemic by indicating how many beds are currently occupied by critically ill patients and thus not available to treat additional patients who may need critical care. ICU occupancy is defined as the number of staffed adult ICU beds occupied in acute care hospitals. ICU occupancy includes all patients in the ICU, not only patients with COVID-19.

This metric is calculated by dividing the number of staffed adult ICU beds occupied each day by the total number of staffed adult ICU beds available and multiplying by 100. A 7-day average is calculated by averaging the percent over the most recent 7 days. The thresholds for this metric are:

  • Low: Less than 90%
  • High: 90% or more

Data from WA HEALTH are used for this metric. Metrics are calculated using the most recent complete data for a single Sunday–Saturday week.

Percent positivity
The 7-day percent positive of COVID-19 tests metric describes how widespread infections are and if sufficient testing is occurring. A test is defined as a molecular test, including PCR, performed on an individual who has not previously tested positive for COVID-19 by molecular testing. Tests are assigned to the specimen collection date. Antigen and antibody tests are not included in this metric.

This metric is calculated by dividing the number of positive COVID-19 tests by the total number of tests performed in a 7-day period and multiplying by 100. The thresholds for this metric are:

  • Low: Less than 10%
  • High: 10% or more

Data from WDRS and the DOH negative lab dataset are used for this metric. Metrics are calculated using the most recent complete data for a single Sunday–Saturday week.