COVID19CountyMonitoringOverview Blueprint for a Safer Economy



Blueprint for a Safer Economy

California has a blueprint for reducing COVID-19 in the state with revised criteria for loosening and tightening restrictions on activities. Every county in California is assigned to a tier based on its test positivity and adjusted case rate for tier assignment. Additionally, a health equity metric took effect on October 6, 2020. In order to advance to the next less restrictive tier, each county will need to meet an equity metric or demonstrate targeted investments to eliminate disparities in levels of COVID-19 transmission, depending on its size. The California Health Equity Metric is designed to help guide counties in their continuing efforts to reduce COVID-19 cases in all communities and requires more intensive efforts to prevent and mitigate the spread of COVID-19 among Californians who have been disproportionately impacted by this pandemic.

Updates as of 02/23/2021:

Additional information about the Blueprint:

Plan for Reducing COVID-19 and Adjusting Permitted Sector Activities to Keep Californians Healthy and Safe

This guidance outlines an updated framework for a safe progression of opening more businesses and activities in light of the pandemic. The framework for this guidance is informed by increased knowledge of disease transmission vulnerabilities and risk factors and is driven by the following goals:

  1. To progress in phases based on risk levels with appropriate time between each phase in each county so impacts of any given change can be fully evaluated.

  2. To aggressively reduce case transmission to as low a rate as possible across the state so the potential burden of flu and COVID-19 in the late fall and winter does not challenge our healthcare delivery system's ability to surge with space, supplies and staff.  Also, with winter weather pushing more activities indoors, low levels of transmission in the community will make large outbreaks in these riskier settings less likely.

  3. To simplify the framework and lay out clear disease transmission goals for counties to work towards.

Tier Framework

This framework lays out the measures that each county must meet, based on indicators that capture disease burden, testing, and health equity. A county may be more restrictive than this framework. This framework also notes signals of concern, including impacted healthcare capacity that may lead towards a dimming intervention. This framework replaces the former County Data Monitoring metrics.  As the COVID-19 pandemic continues to be an evolving situation and new evidence and understanding emerges, the California Department of Public Health (CDPH), in collaboration with other State officials, will continue to reassess metrics and thresholds.

See chart below for the framework metrics as set according to tiers based on risk of community disease transmission. Calculation of metrics is described in Appendix 1. Description of the Health Equity Metric can be found on the Health Equity Metric page.


Community Disease Transmission Chart

Metrics with values greater than or less than tier cut points by 0.05 are rounded up or down using conventional rounding rules.

^Excludes state and federal inmates, ICE facility residents, State Hospital inmates and US Marshal detainees

*Population denominators from the Department of Finance: State Population Projections - Total Population by County- Table P-1 

**Case rate will be determined using cases confirmed by PCR

*** Counties are assigned a tier based on two metrics: test positivity and case rate. Large counties with populations greater than approximately 106,000 must also meet the health equity metric described on the Health Equity Metric page in order to advance to a less restrictive tier.

The case rate is adjusted based on testing volume per 100,000 population as described below.  Due to variability in data, this adjustment does not apply to small counties (defined as those with a population less than 106,000 residents).

As counties focus on increased testing in their health equity quartiles and to support school openings, they are likely to experience an increased number of cases. We want to avoid disincentivizing increased testing, provided that test positivity is low and there is sufficient capacity for contact tracing and isolation. We are therefore increasing the adjustment for higher volume testing. 

  • For counties with testing volume above the state median, the factor is less than 1, decreasing in a linear manner from 1.0 to 0.5 as testing volume increases from the state median to 2x the state median.  The factor remains at 0.5 if the testing volume is greater than 2x the state median.

  • For counties with testing volume below the state median, the factor is greater than 1, increasing in a linear manner from 1.0 to 1.4 as testing volume decreases from the state median to zero.  However, this adjustment for low testing volume will not be applied to counties with a test positivity < 3.5%.

California COVID-19 Case Rate Adjustment Factor
Testing VolumeCase Rate Adjustment Factor*
01.4
0.25* State Median1.3
0.50* State Median1.2
0.75* State Median1.1
 State Median1
1.25* State Median0.875
1.5* State Median0.75
1.75* State Median0.625
2.0*State Median and above0.5

  • Counties with fewer than 106,000 residents, will be exempted from case rate adjustments, and counties with test positivity <3.5% will be exempted from adjustment for testing rates lower than the state median.

  • If the two metrics are not within the same tier, the county's tier assignment will be determined by the more restrictive of the two.  For example, if a county's test positivity corresponds to tier 3 (orange, moderate), but the case rate corresponds to tier 1 (purple, widespread), the county will be assigned as tier 1. Movement will be determined by criteria described below.

Moving through the Tiers

Rules of the framework:

  1. CDPH will assess indicators weekly on Mondays and release updated tier assignments on Tuesdays.

  2. A county must remain in a tier for a minimum of three weeks before being able to advance to a less restrictive tier.

  3. A county can only move forward one tier at a time, even if metrics qualify for a more advanced tier.

  4. If a county's adjusted case rate for tier assignment and test positivity measure fall into two different tiers, the county will be assigned to the more restrictive tier.

  5. The health equity metric is applied to jurisdictions with populations greater than 106,000. Rules of the health equity metric are described on the Health Equity Metric page.

  6. City local health jurisdiction (LHJ) data will be included in overall metrics, and city LHJs will be assigned the same tier as the surrounding county

  7. An LHJ may continue to implement or maintain more restrictive public health measures if the local health officer determines that health conditions in that jurisdiction warrant such measures.

  8. Tier status goes into effect the Wednesday following each weekly tier assignment announcement on Tuesdays.

To advance:

  1. A county must have been in the current tier for a minimum of three weeks.

  2. A county must meet criteria for movement to the next less restrictive for the prior two consecutive weeks in order to progress to the next tier; which can be achieved by either or combination of criteria described below:

    1. Meeting the Adjusted Case Rate, Test Positivity, and Health Equity metric criteria for a less restrictive tier.

    2. Meeting the criteria for movement to the next less restrictive tier through health equity accelerated progression.

To move back:

  1. During the weekly assessment, if a county's adjusted case rate and/or test positivity has fallen within a more restrictive tier for two consecutive weekly periods, the state will review the most recent 10 days of data, and if CDPH determines there are objective signs of improvement the county may remain in the tier.  If the county’s most recent 10 days data does not show objective signs of improvement the county must revert to the more restrictive tier. For subsequent weekly assessments, the above rules apply.

  2. At any time, state and county public health officials may work together to determine targeted interventions or county wide modifications necessary to address impacted hospital capacity and drivers of disease transmission, as needed, including movement across more than one tier. Key considerations will also include the rate of increase in new cases and/or test positivity, more recent data as noted above, public health capacity, and other epidemiological factors.

  3. Counties with a population less than 106,000 will have a small county criteria applied to it to ensure movement to a more restrictive tier is appropriate. Description of the small county framework is below. 

  4. Counties will have three days, beginning the Wednesday after tier assignments are announced on Tuesdays, to implement any sector changes or closures unless extreme circumstances merit immediate action.

Small County Framework

Because California's case rate metric is normalized per 100,000 population, a number of counties with small populations have experienced large swings in their daily case rate as a result of a small number of newly reported cases. For some counties, this has raised the specter of needing to move back to a more restrictive tier despite overall disease stability and a demonstrated ability to trace, follow up with, investigate and support cases.

For example, once a small county is in yellow tier, a small number of cases – as low as 1 case per week for 2 consecutive weeks – could cause it to return to a more restrictive tier. While the overall proportion of cases may be the same as a larger county, the absolute number of cases is also an important consideration in gauging county capacity to control transmission through disease investigation, contact tracing and supportive isolation. 

It is not in the interest of the public health of communities to close or restrict entire business sectors on the basis of such a small number of cases, and in some situations a small swing in week over week case counts can move a county from yellow tier all the way to purple tier. Because the state wants to avoid swift shifts in tier status based on small absolute case number changes, we are creating an alternate case assessment measure to apply to small counties. Small counties are defined as having fewer than 106,000 residents.[1]

Alternate Case Assessment Measure.  Small counties are subject to all existing Blueprint rules (test positivity thresholds, minimum duration of 3 weeks in a tier before moving to a less restrictive tier, inability to skip over a tier while moving from more restrictive to less restrictive tier designations, etc.) with the exception of the case rate thresholds as delineated below. 

The alternate case assessment measure provides a small county protection against sudden tier changes as a result of small increases in cases. 

For a small county that has test positivity that meets the threshold of that county's currently assigned tier, but is flagged for potentially moving to a more restrictive tier based on its weekly case rate assessment, the following criteria shall be applied in lieu of the Blueprint case rate thresholds. 

If the county exceeds the following absolute weekly case numbers based on its population and tier for two consecutive weeks, it will be required to move to a more restrictive tier:

 

Current TierPop ≤ 35KPop 35K-70KPop 70K-106K
Yellow71421
Orange142128
Red354249


Movement into Yellow Tier

In moving from purple to red or red to orange tiers, small counties are subject to all existing Blueprint rules (test positivity thresholds, minimum duration of 3 weeks in a tier before moving to a less restrictive tier, inability to skip over a tier while moving from more restrictive to less restrictive tier designations, etc.).

For a small county to move from the orange to yellow tier, it must meet the existing test positivity threshold of less than 2%.  However, in lieu of meeting the established daily case rate threshold for yellow tier of less than 1 case per 100,000, a small county is allowed to have a daily case rate of less than or equal to 2 cases per 100,000.  Of note, these are the same parameters used for the health equity acceleration criteria to yellow tier.  


[1] Twenty-two California counties have a population of less than 100,000.  Sutter, which has a population of 106,000 is also included as it shares a health officer with Yuba County.  Counties below this size have similar challenges and opportunities in controlling COVID-19 transmission and generally do not have major or large, densely populated cities. This distinction factors into how rapidly COVID-19 transmission can increase beyond households and the ability of the county to rapidly identify and contain outbreaks with existing contact tracing, isolation and quarantine resources.

Risk Criteria

Activities and sectors will begin to open at a specific tier based on risk-based criteria (PDF), as outlined below.  Lower risk activities or sectors are permitted sooner and higher risk activities or sectors are not permitted until later phases.  Many activities or sectors may increase the level of operations and capacity as a county reduces its level of transmission.

Criteria used to determine low/medium/high risk sectors

  • Ability to accommodate face covering wearing at all times (e.g. eating and drinking would require removal of face covering)

  • Ability to physically distance between individuals from different households

  • Ability to limit the number of people per square foot

  • Ability to limit duration of exposure

  • Ability to limit amount of mixing of people from differing households and communities

  • Ability to limit amount of physical interactions of visitors/patrons

  • Ability to optimize ventilation (e.g. indoor vs outdoor, air exchange and filtration)

  • Ability to limit activities that are known to cause increased spread (e.g. singing, shouting, heavy breathing; loud environs will cause people to raise voice)

Schools

Schools may reopen for in-person instruction based on equivalent criteria to the K-12 School Guidance.  Schools in counties within the Purple Tier are not permitted to reopen for in-person instruction, with exceptions outlined in the K-12 School Guidance. See the guidance and the K-12 Schools FAQ for additional information on school re-opening eligibility criteria under the Blueprint.  

As stated in the K-12 School Guidance, schools are not required to close if a county no longer meets relevant school re-opening criteria (e.g., goes from Red Tier to Purple Tier or has adjusted county case rates ≥25/100,000 population) but may consider increasing testing per the CDPH supported testing framework.  

County Tier Adjudication Process

For more information, visit our County Tier Adjudication Request page. 

APPENDIX 1: Calculation of metrics

MetricDefinition
Case Rate (rate per 100,000 excluding prison cases, 7-day average with 7-day lag)

Calculated as the average (mean) daily number of COVID-19+ cases, this excludes: (a) persons out of state or with unknown county of residence and (b) persons incarcerated at state or federal prisons, ICE facilities, US Marshal only detention facilities or Department of State Hospitals (identified as cases with an ordering facility name or address associated with these locations), over 7 days (based on episode date), divided by the number of people living in the county/region/state. This number is then multiplied by 100,000. Due to reporting delays, there is a 7-day lag built into this calculation. For example, for data updated through 8/22/20, the case rate will be dated as 8/15/20 and will include the average case rate from 8/9/20 - 8/15/20.

Linear adjusted case Rate per 100,000 per day, excluding prisoners (7-day average with 7-day lag)

Calculated as the case rate multiplied by a case rate adjustment factor that is based on the difference between the county testing volume (testing volume, tests per 100,000 per day, described below) and the median county testing volume calculated across all counties. The median testing volume thus forms an anchor for this adjustment and is recalculated every week to account for evolving testing trends. For counties with a testing volume above the median, the adjustment factor is less than 1, decreasing in a linear manner from 1.0 to 0.5 as testing volume increases from the anchor point to 2x that value. The adjustment factor remains at 0.5 if the county testing volume is greater than 2x the state median. For counties with a testing volume below the state median, the adjustment factor is greater than 1, increasing in a linear manner from 1.0 to 1.4 as county testing volume decreases from the state median to zero. The linear adjustment formula can be expressed mathematically as follows:

For counties testing above the state median:

1-(((county testing rate – state median testing rate)/state median testing rate) * 0.5)

For counties testing below the state median:

 1-(((county testing rate – state median testing rate)/state median testing rate) * 0.4)

There are two conditions in which this formula is not applied. The first is small counties, those with a population less than approximately 100,000 based on CA Department of Finance population projections (see reference * in tier framework table). The small county exception prevents potential spurious adjustment due to fluctuations in testing influenced by secular events unrelated to underlying transmission risk. As a second condition for exception from the adjustment, counties with a testing volume below the state median and testing positivity < 3.5% are not adjusted, based on the assumption that volume of testing in these counties may not need to be as high with low test positivity. Under both these conditions, the adjusted case rate is equal to the unadjusted rate.

Overall testing Positivity, excluding prisoners over 7-days (PCR only, 7-day lag)

​Calculated as the total number of positive polymerase chain reaction (PCR) tests for COVID-19 over a 7-day period (based on specimen collected date) divided by the total number of PCR tests conducted; this excludes tests for: (a) persons out of state or with unknown county of residence and (b) persons incarcerated at state or federal prisons, ICE facilities, US Marshal only detention facilities and Department of State Hospitals (identified as cases with an ordering facility name or address associated with prison/state hospitals locations). This number is then multiplied by 100 to get a percentage. Due to reporting delay (which may be different between positive and negative tests), there is a 7-day lag.

Example: For cumulative lab data received on 6/30/20, reported test positivity is dated as 6/23/20 and is calculated based on tests with specimen collection dates from 6/17-6/23

Tests per 100,000 per day, excluding prisoners (7-day average with 7-day lag)

Calculated as the number of polymerase chain reaction (PCR) tests per day over a 7-day period (based on specimen collection date), excluding tests for persons incarcerated at state or federal prisons, ICE facilities, US Marshal only detention facilities and Department of State Hospitals  (identified as cases with an ordering facility name or address associated with prison/state hospitals locations), and divided by the number of people living in the county/region/state. This number is then multiplied by 100,000. Due to reporting delay, there is a 7-day lag included in the calculation.

Example: For cumulative lab data received through 8/22/20, the reported 7-day average number of tests will be dated as 8/15/20 and will include PCR tests with specimen collection dates from 8/9/20 - 8/15/20.

 Data Source: CalREDIE