WebMD BlogsWebMD Interviews

Unpacking COVID Data: What to Know

photo of graph
August 11, 2020
From the WebMD Archives

By Victoria Giardina

There’s no shortage of data about the coronavirus pandemic. But with so much information it can be overwhelming to know which numbers are most impactful and which sources are most credible.

F. Perry Wilson, MD, MSCE of Yale School of Medicine, talked about some of the most trusted online tracking resources and how to properly navigate their approaches.

WebMD: What data sources do you find particularly useful?

Wilson: The Johns Hopkins is the sort of gold standard reporting source which has a great graphical interface that you can easily find on the web. The COVID tracking project, which collates testing as well as positivity data from every state in the country (run by The Atlantic) is great if you want to get a sense of those test positivity rates. They show you hospitalization rates and death rates on a state-by-state level, so those are some really good resources.

WebMD: What’s more important: hospitalization rates or positive test results?

Wilson: I think positive test results are a leading indicator of spread in an area so as those start to trend up, that’s the first warning sign that something isn’t going right. From a practical standpoint, it’s the hospitalization rates that really scare us because the disaster scenario is a hospital or ICU being overwhelmed.

WebMD: Where does the CDC stand among all these resources?

Wilson: I don’t think the CDC does as well with data visualization and interactivity that you get from other online resources like The COVID Tracking Project and The Johns Hopkins dashboard that so many of us have been using. Nevertheless, the CDC is still the governmental agency which is cast with making these guidelines.

WebMD: Are news sites or university medical centers more credible?

Wilson: I think you can get lost in the data dashboard sometimes so I think there is a role for good science journalism, and I’m a big advocate for it. Agendas and different viewpoints can be amplified by social media, but you want to trust publications with dedicated science writers who are tasked with a health or science beat. You want some level of expertise from a journalist who can untackle medical information, especially during COVID-19.

WebMD: Can you explain the tracker Rt live – which looks at the virus’ transmission rate in real time -- and its unique approach? 

Wilson: A lot of epidemiologists would tell you to be incredibly cautious about interpreting a reproductive number over time at all. To some extent, it’s satisfying to look at graphs that look like the transmission is going down but the data that drives that is incomplete, so the models are somewhat incomplete.

The fact of the matter is that people move around quite a bit and in the absence of a stay-at-home order, people are crossing town and state lines all the time, so I tell people not to look at too much granular data than the state level. Once you start looking at counties, you really might get misled.

Here are some of the sites experts chose as their top data sources, and what they offer:

Johns Hopkins Coronavirus Resource Center

Johns Hopkins features confirmed data on global and US-related cases and deaths, along with pandemic news, tracking graphics, testing trackers, “curve” updates, contact tracing updates and educational learning tools. It also provides data by state, such as trends in cases and testing and looks at positivity rate, or the percent of COVID tests taken that come back positive. A lower positive rate shows better control of the virus. 

The University also has a Testing Insights Initiative which features data and expert analysis together. It is designed to help policymakers and the public understand the trajectory of the pandemic to make future decisions.


Politico features a large graphic of confirmed  COVID-19 cases, and a U.S. map that allows users to click on red zones to obtain a state breakdown of data. A larger red circle in a particular region indicates a more at-risk zone. Other bar charts below the graphic highlight each state’s population and how many test increases present since the week prior.

The COVID Tracking Project (The Atlantic)

The COVID Tracking Project (The Atlantic) is where Politico pulls its data from and is the tracking resource The White House selected it as the best source of information for daily U.S. test numbers, according to its “Opening Up America Again” testing strategy. It’s essentially a one-stop-shop for credible COVID-19 information, including a COVID Racial Data Tracker that looks at deaths by race and ethnicity.

COVID Exit Strategy

This site was created by a group of public health and crisis experts who have vast experience working at the White House, Department of Health and Human Services and on the Ebola epidemic of West Africa. The Exit Strategy identifies critical interventions needed to stop the spread of COVID-19 and urges government decision-makers to apply them. It shows how states are trending and includes data on measures such as trends in case numbers, ICU beds, testing and contract tracing. 

The New York Times ‘Coronavirus in the US’

The New York Times’ tracker is a detailed U.S. map for COVID-19 hot spots, organized by county. It is the most specific and regional map for local data and shows what states have increased, decreased and mostly leveled in its case reports. It also looks at testing by state and whether they are above or below recommended levels.


The CDC offers information on total cases, as well as updates on new cases and new deaths. The page is updated daily based on data confirmed at 4:00 p.m. EST the day before. It also features cases in the US and cases and deaths by county. Its numbers on cases and deaths tends to lag behind others such as Johns Hopkins  and The New York Times

The governmental health hub also offers statistics that estimate hospital capacity by the state in its ‘Percentage of Inpatient Beds Occupied by COVID-19 Patients’ graphic. The estimates are based on data submitted by acute care hospitals.

TIME Coronavirus Map

Showing per capita cases in the U.S., the TIME Coronavirus Map displays which states are flattening the curve. It features a “How Has COVID-19 Spread in Your State” tracking system, accredited to Johns Hopkins University Center for Systems Science and Engineering. The tracking resource also highlights how the U.S. compares to other countries in international spread.

Prevent Epidemics

Organized as more of a researcher’s dataset, Prevent Epidemics features downloadable reports for (1) tracking COVID-19 in the United States, (2) essential indicator availability by state, (3) essential indicators for states, (4) example data dashboards and (5) a data dictionary of essential and recommended information. Its stratified data is weekly, cumulative and based on 15 essential indicators with dashboards to support its findings. Some indicators include newly-confirmed cases per capita, percentage of new cases linked to at least one other case, and percentage of screening and diagnostic tests, positive by date.

The organization also offers educational COVID-19 insights to both national and international audiences.

Rt Live

Offering a unique perspective on COVID-19 tracking is Rt live, a resource that outlines Rt, a key measure of how fast the virus is growing. In other words, it’s the average number of people who become infected by an infectious person.

If Rt is above 1.0, the virus will spread quickly and when Rt is below 1.0, the virus will stop spreading. Data is organized in a horizontal bar diagram with states below 1.0 expressed in green and above 1.0 in red. The resource also features a state breakdown below the nationwide data.


WebMD Blog
© 2020 WebMD, LLC. All rights reserved.

More from the WebMD Interviews Blog

  • photo of coronavirus el paso

    El Paso COVID Surge: 'It's Just Constant'

    With nearly 30,000 active COVID-19 cases and a test positivity rate of 20% according to the city's dashboard, El Paso, TX,  is averaging about 1,000 new cases a day.

  • coronavirus vaccine

    CDC’s Messonnier Says She Trusts COVID Vaccine Process

    Nancy Messonnier, MD, director of the National Center for Immunization and Respiratory Diseases at the CDC, talks about the COVID vaccine rollout and having flu season in the middle of a pandemic.

View all posts on WebMD Interviews

Latest Blog Posts on WebMD

View all blog posts

Important: The opinions expressed in WebMD Blogs are solely those of the User, who may or may not have medical or scientific training. These opinions do not represent the opinions of WebMD. Blogs are not reviewed by a WebMD physician or any member of the WebMD editorial staff for accuracy, balance, objectivity, or any other reason except for compliance with our Terms and Conditions. Some of these opinions may contain information about treatments or uses of drug products that have not been approved by the U.S. Food and Drug Administration. WebMD does not endorse any specific product, service or treatment.

Do not consider WebMD Blogs as medical advice. Never delay or disregard seeking professional medical advice from your doctor or other qualified healthcare provider because of something you have read on WebMD. You should always speak with your doctor before you start, stop, or change any prescribed part of your care plan or treatment. WebMD understands that reading individual, real-life experiences can be a helpful resource, but it is never a substitute for professional medical advice, diagnosis, or treatment from a qualified health care provider. If you think you may have a medical emergency, call your doctor or dial 911 immediately.

Read More