After I made my post about the percentage of schools with school outbreak-associated cases I was curious about the percentage of students with school outbreak-associated cases. I got the 2021 student enrollment data from the Maryland State Department of Education’s report card. I then divided the county enrollment by the number of outbreak-associated cases in public schools as published by the Maryland Health Department on September 1, 2021. I had previously coded each of the schools from the September 1, 2021 data release as public or private. Then I made a map using Datawrapper.

As a note, many schools systems have not opened as of September 1, 2021, and reporting to the Maryland Health Department may be delayed.

As a parent, it is good to see the number of cases in perspective. Although I know that every person’s risk tolerance is different.

According to the previous map I made, 16% of Frederick County Public Schools have a school outbreak-associated case. That seems like a lot, at least to me. However, when I look at this map, I see that less than one-tenth of a percent of Frederick County public school students, 0.07%, have a school-associated outbreak case. That seems less alarming. As to which portrayal is better, at this point I do not know. I guess I will have to wait and see.

What is also interesting about this map is that it is normalized. Both St. Mary’s County Public Schools and Prince George’s County Public School have 6 school outbreak-associated cases. For St. Mary’s County Public Schools it is 0.03% of the student body. For Prince George’s County Public Schools it is 0.00% of the student body, due to rounding because the student body of Prince George’s County is much larger than that of St. Mary’s County.

UPDATE: The Maryland Health Department numbers include teachers and staff. The denominator in the map below just includes students. I will have to see if I can fix these numbers and create an updated map. This is why checking your data is important.

Notes about the Data

These notes are copied from the Maryland Department of Health website.

Note: This dataset reflects public and non-public K-12 schools in Maryland that have COVID-19 outbreaks. Data are based on local health department reports to MDH, which may be revised if additional information becomes available. This list does not include child care facilities or institutes of higher education. Schools listed meet 1 or more of the following criteria:

Classroom/cohort outbreak definition:    1) At least two confirmed COVID-19 cases among students/teachers/staff within a 14-day period and who are epidemiologically linked, but not household contacts; or

School-wide outbreak definition:    

2) Three or more classrooms or cohorts with cases from separate households that meet the classroom/cohort outbreak definition that occurs within 14 days; or
 3) Five percent or more unrelated students/teachers/staff have confirmed COVID-19 within a 14 day period (minimum of 10 unrelated students/teachers/staff).

Cases reported reflect the current total number of cases. Schools are removed from the list when health officials determine 14 days have passed with no new cases and no tests pending. Archival data is available through the COVID-19 open data catalogue. These data are updated weekly on Wednesdays during the 10 a.m. hour. MDH is continuously evaluating its data and reporting systems and will make updates as more data becomes available.

I pulled data on September 1, 2021, to make the above map. I provided the information on whether a school is public or private. All errors are my own. This map is not official, it is primarily for the purpose of me exploring the visualization features and keeping track of what I learned.

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