Covid-19 Data Dashboards

The below graphs illustrate data on Covid-19 cases in Delaware County and Radnor Township as provided weekly by Chester County (click here for county; click here for Radnor). According to Chester County, all data is updated each time a report is published as additional data becomes available through laboratory reporting and case investigations.

Cumulative Incidence Rate per 100,000

Cumulative incidence rate is a public health measure that summarizes the number of new Covid-19 cases. The lower the incidence rate, the lower the number of new cases. This measure is calculated by dividing the total number of confirmed and probable cases by the population (Delaware County: 564,751; Radnor: 31,710*) for a specific time period, and is expressed as a rate per 100,000 people. The rate is calculated for 7 day periods beginning with the most current week as Week 1 and looking back three weeks.

Percent Positivity

Percent positivity is a public health measure that shows the percentage of all PCR Covid-19 tests performed that are positive. This measure is calculated by dividing the total number of positive PCR tests by the total number of all PCR tests (positives +negatives) for a specific time period, and is expressed as a percent. If individuals are tested multiple times, each test result is counted. The percent is calculated for 7 day periods beginning with the most current week as Week 1 and looking back three weeks.

*Public school district data is provided using population data from the 2018 fact finder values found on the Census.gov site.