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Introducing a Critical COVID Metric: Daily New Cases Per 100K Population


Today, we are adding an important fifth metric to our COVID warning system: “daily new cases per 100K population” (also referred to by epidemiologists as “incidence”). The addition of this metric rounds out our warning system by incorporating a measure of how much COVID there is in each community today. Our previous metrics focused on direction of change and preparedness, but incidence...

Changes to How We Assess Contact Tracing


Based on discussions with public health experts and policy makers, we are responding to feedback on the way we assess contact tracing. We have removed the critical (red) range for contact tracing and it will no longer be possible to be marked critical (red) due to low numbers of contact tracing staff alone. While low numbers of contact tracing staff should be acknowledged, it doesn’t indicate an...

What is Incidence?


What is incidence?  Incidence is a measure of new confirmed COVID cases per day. To ensure incidence can be compared across geographies, we calculate it as a proportion of the population — specifically, new daily cases for every 100,000 people. Adding a case incidence metric depicts risk more accurately, since it takes the overall number of cases into account. We calculate incidence as...

Calculating better Infection Growth Rates (Rt) for more communities


Today we are making a change to the way we calculate Rt to better serve lower population regions and regions with lower case counts as well as to improve the timeliness of our Rt metric. We want to be more timely in letting people know when COVID is growing or shrinking in their communities, and this hopefully helps people understand how policies and actions are able to achieve different outcomes.

Launching COVID Alerts


Covid Act Now is a nonprofit organization with a mission to help save lives. To further that mission, we’re excited to launch COVID Alerts. COVID Alerts let you know when the COVID threat level — based on metrics critical to monitoring COVID, such as infection growth rate and ICU capacity — changes in your county or state. It’s easy to sign up! Just visit: Then enter...

Model Changes: Adding a Fourth Color


Previously, our model depicted risk in three colors: red, yellow, and green. We have now added a fourth color: orange. Using four colors allows the Covid Act Now threat scores to be more nuanced, reflecting the more messy, complicated reality of COVID in America. The addition of a fourth color (orange) allows red to be reserved for truly critical situations. Here are the four colors and what they...

Social Sharing


If you see a graph on Covid Act Now’s website and want to share it, now you can! We recently launched social sharing, so you can share data about your state or county on Facebook, Twitter, LinkedIn, or other social media. You can also embed Covid Act Now graphs in presentations, in other documents, or on your website. Here’s a quick guide: First, find the graph you want to share. In the upper...

Where Does Our Data Come From?


Want to know where Covid Act Now’s data comes from? We’ve created an easy-to-follow slide deck to answer all your questions about where we get the data that feeds our modeling and metrics.  Our guiding principles for selecting data sources are availability, authoritativeness, and timeliness. The slides explain the inputs for each of our metrics (e.g., the number of new daily COVID cases or the...

Our Newest Metric: Contact Tracing


Today, we’re excited to announce a fourth metric added to our COVID warning system: contact tracing. We will lay out how we calculate whether states have sufficient contact tracing capacity, and why we think it is an important metric to assess reopening. Why Does Contact Tracing Matter? When people contract the virus, they do not show symptoms right away. Even as states begin to reopen, people...

Changes to Model Parameters


We recently changed a few of our model parameters. We wanted to share what changed and why. The epidemiological model we use to track COVID is an SEIR model. An SEIR epidemiology model tracks the flow of a population between four states in relation to a disease (in this case, COVID). Those four states are susceptible (S), exposed (E), infected (I), and recovered (R). Mash those four together and...

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