What is NOWCast?

It is difficult to reliably estimate COVID-19 trends for most of the 95 counties in Tennessee. Most counties are small and changes of only a few cases a day can mean dramatic changes in disease rates. Additionally, overworked labs and public health staff mean that data may not be updated every day. NOWcast uses modern statistical methods to estimate the trends that describe all these noisy data. The NOWcast groups together similar counties, then estimates recent changes in disease rates, and projects those changes forward. In nation-wide validation, the NOWcast accurately describes county-level trends one week into the future.


What do negative numbers on the dashboard mean?

When the TN Department of Health needs to make corrections to a previous day’s data, they do it by putting a correcting entry in a later day’s numbers. For instance, if they overcount tests by 6,000 on Tuesday, then on Wednesday they’ll put in -6,000 tests to correct the total. That can make it appears as though there were -6,000 tests administered on Wednesday, which obviously isn’t possible. It’s like correcting entries in financial accounts.


What do dashes (-) on the dashboard mean?

This indicates that data is not available or to mask divide by zero errors. This should only occur in counties with very few cases.


What does “% Change per capita” mean?

Per capita figures are derived by dividing a metric’s value by the US Census Bureau’s 2019 estimate of population in the area. Percent change per capita figures are an expression of the difference between today and last week’s values divided by last week’s value. This metric gives you a sense of how much a metric is changing in a way that controls for population.


Who is included in “UT Home Population”?

Aggregate of students, faculty, and staff. Students counts are from the official Fall 2019 census based on home addresses and only include in-state students. Faculty and staff are any active employees that worked during the 2019 fiscal year (July 2018 – June 2019) based on home addresses.


What does the tool tip mean when I hover over a county in the table to the left?

“UT pop. residing in county last fall” is also known as the UT Home Population (see question above). “UT pop. in county at campus last fall” is the aggregate count of students, faculty, and staff that were learning or working at the respective campus in the selected county (including out-of-state and international).


What is the difference between “UT pop. residing in county last fall” and “UT pop. in county at campus last fall”?

“UT pop. residing in county last fall” includes only students, faculty, and staff who have a permanent address in Tennessee. “UT pop. in county at campus last fall” includes students, faculty, and staff that were learning or working at the respective campus in the selected county (including out-of-state and international).


Why are percent of tests not available for “New cases and statewide percent of tests by age group” visual?

The Tennessee Department of Health does not provide testing and outcome metrics at a county level.


Why are hospitalizations not included in the doughnut chart when I hover over recoveries, active, or death counts?

Hospitalizations are included in the active case counts as provided to the Tennessee Department of Health (recoveries, active, hospitalizations, and death cases are not exclusive categories).


The number of positive tests and total tests seem low, why?

Total case positivity rate is calculated over the past seven (7) days and therefore excludes any tests prior. Hovering over the total case positivity rate visual will give you a rolling trend of the positivity rate.


The number of test in relation to the tested per 100K is different, why?

Total case positivity rate is calculated over the past seven (7) days and therefore excludes any tests prior. Tested per 100K and percent of population metrics include all data since data collection began for that county.


How does TN Department of Health learn about cases of COVID-19?

Cases of COVID-19 are reported to the Tennessee Department of Health (TDH) by clinicians and laboratories across the state. Initially, public health has fairly limited information about each person that has tested positive, such as their name, date of birth, and address. Public health professionals contact every case of COVID-19 statewide to interview them and learn more about their illness, exposures and contacts.


Why did the number of cases in my county decrease today?

The information that TDH receives from clinicians and laboratories is sometimes incomplete or occasionally incorrect. As we work to publish updated case counts and basic information on our website as quickly as possible, sometimes this information changes as it is updated, and correct information is learned during the investigation. This may mean that a case can move from one county to another once the patient’s county of residence is confirmed during their interview.


How does the state determine if someone died from COVID-19 versus another cause of death?

If someone had COVID-19 when they died, they will be counted as a COVID-19 death. An exception to this is when a case died of something completely independent to COVID-19, like due to a car wreck.


Is the number of individuals hospitalized a cumulative count, or is it currently how many are in the hospital?

Hospitalization data reflect the cumulative (total) number of cases that were ever hospitalized from COVID-19. It does not reflect the number of people currently hospitalized. Cases among Tennessee residents are counted by their county of residence. Residents of other states who were tested at Tennessee healthcare facilities or laboratories are counted as “Out of TN.”


Why does the State data not match the data my county is reporting?

Laboratory reports of positive cases are reported to metro and local health departments as soon as results are available. State numbers are updated at 2 p.m. CDT daily. There may be a lag in the reporting of cumulative numbers at the state level. Metro Health Departments may also include individuals from out of Tennessee in their localized counts if the case is remaining in that county throughout the course of their illness.


Who reports data to the State Health Department?

COVID-19 is a reportable condition in Tennessee. This means that clinicians and laboratories are required to report known cases to the Department of Health within 24 hours.


How often do labs and providers report data?

The Department of Health receives lab results (both positive and negative) from laboratories daily, and data from healthcare providers within 24 hours of identifying a case of COVID-19.


What is the source and timeframe of Tennessee population numbers that are used for comparisons?

All Tennessee population figures used as comparisons in this dashboard are obtained from the U.S. Census Bureau’s 2019 Vintage Housing and Population Estimates.