Methods and Metrics

Methods -thresholds for each indicator are described below. Source of COVID-19 case data is SC DHEC:

  • Indicators

*Cases Per Day Per 100k Population (for the week of...) – This is the 7-Day average of the number of reported cases per day per 100k residents, as reported on the South Carolina DHEC site; it is reported on a weekly basis, and is the total number of confirmed cases combined with the total number of probable cases for Chester and Lancaster Counties. When the cases are less than 5 for any county, they are "suppressed" from the CDC, and we enter it as zero in our calculation of the average. Available at: https://scdhec.gov/covid19/sc-testing-data-projections-covid-19

*Test Positivity  – This number is the 7-Day average of the percent of positive tests, determined using the Test/Test method. This number is reported by South Carolina DHEC on a weekly basis, available at: https://scdhec.gov/covid19/south-carolina-county-level-data-covid-19

*Percentage of Total Population Vaccinated (2 doses)– This is the percentage of the aggregate number of people who have currently been vaccinated by county with two doses of a vaccine. This metric does not include individuals who may move across state lines in order to access vaccines. This data is reported by CDC and is available at: https://covid.cdc.gov/covid-data-tracker/#county-view?list_select_state=all_states&list_select_county=all_counties&data-type=CommunityLevels

*Percentage of Total Population Boosted (3 doses)– This is the percentage of the number of people who have currently been given 2 doses of a vaccine and 1 dose of a booster by county. This data is reported by CDC and is available at: https://covid.cdc.gov/covid-data-tracker/#county-view?list_select_state=all_states&list_select_county=all_counties&data-type=CommunityLevels

*Percent of Staffed Hospital beds Utilized for Covid-19 Care–
This is the percentage of the beds being utilized by Covid-19 patients that are staffed with a nurse or doctor. This data is reported by CDC and is available at: https://data.cdc.gov/Public-Health-Surveillance/United-States-COVID-19-Community-Levels-by-County/3nnm-4jni

*Average Daily Covid-19 Hospital Admissions Per 100k Population– This is the average number of Covid-19 patients admitted to hospitals per 100k people. This data is reported by CDC and is available at: https://data.cdc.gov/Public-Health-Surveillance/United-States-COVID-19-Community-Levels-by-County/3nnm-4jni

Covid-19 Impact Criterion for Level Status:

We use The Center for Disease Control's Community Level Guidelines. We calculate the risk threshold for the combined areas of Lancaster and Chester, from the CDC community level guidelines. These guidelines can be found on the CDC website, as well as further information on how these levels are calculated (Center for Disease Control and Prevention Website). 

In addition to these guidelines, we report on the growth rate of new cases. Growth rates are defined as follows: decreasing, stable, increasing, increasing rapidly.
Decreasing: -6% or less
Stable: -5% through +5%
Increasing: +6% through +30%
Increasing Rapidly: +30% or more

*The Number of Weekly Covid-19 Infections is Undercounted-These numbers are calculated utilizing data reported from DHEC. Available at: https://scdhec.gov/covid19/south-carolina-county-level-data-covid-19. The calculations draw upon Wall Street Journal analysis of Johns Hopkins University and Institute for Health Metrics and Evaluation data. These numbers are updated weekly. Article available at: https://www.wsj.com/articles/why-covid-pandemics-daily-case-count-comes-up-short-in-the-u-s-11653643802

 

*Wastewater Graphics-The graph showing trends in COVID-19 wastewater concentration and reported COVID-19 cases detected from testing over time was derived as follows: (1) We utilized data on daily normalized COVID-19 wastewater concentrations archived by CDC: https://covid.cdc.gov/covid-data-tracker/#wastewater-surveillance; (2) data on the number of cases detected by testing come from SC DHEC, (3) total weekly COVID-19 cases detected by testing was converted to an average daily number of cases of COVID-19 per 100,000 population; (4) since cases detected by testing is a weekly point estimate, we developed a curve for the trend over time by generating a 6th order polynomial regression line utilizing a spline function to allow for comparison to the wastewater data; (5) the trend for each parameter is presented as a smoothed line in a dual axis graphic.

 

  • Growth in Number of Reported COVID-19 Infections: Weekly change of reported infections for the Lancaster region (Percentage change in 7-day average of new infections over the past week).

*These metrics are updated weekly.

GREEN – The percent change in the 7-day average in growth of confirmed cases over the past week is 1% or less (or negative).

YELLOW – The percent change in the 7-day average in growth of confirmed cases over the past week is 2-5%.

RED – The percent change in the 7-day average in growth of confirmed cases over the past week is 6% or greater.

 

  • Trajectory of documented cases (Increasing or Decreasing): Downward trajectory of documented cases within a 14-day period.  

GREEN -There is a negative slope of the trend line (downward trajectory) of the daily 7-day average of number of cases for each of the past two-weeks.

YELLOW -There is a negative slope of the trend line (downward trajectory) of the daily 7-day average of number of cases for one of the past two weeks (one week positive, one week negative).

RED – There is a positive slope of the trend line (upward trajectory) of the daily 7-day average of number of cases for each of the past two-weeks.

 

  • Number of Reported COVID-19 cases in last week: Number of reported cases per week is manageable with regard to medical care and capacity for effective contract tracing.

GREEN -Number of reported cases per week less than 1 per 1,000 population.

(Population = 130,256: equivalent to 13 or fewer cases a week)

YELLOW - Number of reported cases per week is 1-5 per 1,000 population.

(Population = 130,256: equivalent to 13 - 65 cases a week)

RED - Number of reported cases per week greater than 5 per 1,000 population.

(Population = 130,256: equivalent to GT 65 cases a week)

 

  • Diagnostic Testing Availability: Diagnostic testing availability for all people with COVID-19 symptoms.

GREEN – 100% of those meeting criteria and seeking testing receive testing

YELLOW – 80%-99% of those meeting criteria and seeking testing receive testing

RED – Less than 80% of those meeting criteria and seeking testing receive testing

 

  • Return of Diagnostic Test Results: Return of diagnostic test results is done in a timely manner and that allows for rapid contact tracing.

GREEN – Results returned within average of 2 days from sample collection

YELLOW – Results returned within average of 3-4 days from sample collection

RED – Results returned within average of 5 or more days from sample collection

 

  • Hospital Capacity to treat Critical Patients: Area hospitals have ability to treat critical patients requiring hospitalization without resorting to crisis standards.

GREEN – Area hospitals have greater than 15% of total staffed ICU beds available

YELLOW – Area hospitals have between 5% - 15% of total staffed ICU beds available

RED – Area hospitals have less than 5% of total staffed ICU beds available

 

  • New Covid-19 Hospital Admissions per 100k population (7 day average): Number of new hospital admissions to area hospitals, averaged over 7 days.

GREEN – Less than 10 per 100k

YELLOW – 10 to 19.9 per 100k

RED – 20+ per 100k

*Metrics shown reflect the day events occurred, not the day they were reported. DHEC releases data on a weekly basis.