Burbio's Methodology

2021/2022 Academic Year

Burbio audits 5,000 school districts representing over 70% of the US K-12 student enrollment across all 50 states. Districts are checked every 72 hours for changes in enrollment status, mask mandates, vaccine requirements, and testing regimens. Burbio's audit team investigates School District websites, Facebook pages, local news stories and other publicly available information to determine learning mode currently in place. Burbio's audit team also supplements with additional sweeping coverage of all US districts - beyond the 5,000 - to identify additional closures.

2020/2021 Academic Year

Burbio audited over 1,200 school districts representing 47% of the US K-12 student enrollment in over 35,000 schools in 50 states. Districts were checked every 72 hours for changes. See below for details and reconciliation. 

• School District learning modes are categorized as either Traditional, Hybrid or Virtual. Traditional means students attend in-person every day; Hybrid means students are divided into cohorts and attend 2-3 days in-person and 2-3 days virtually.

• Burbio assigns a learning mode to a school district based on the most in-person option available to the general student population. Thus if a district offers both traditional and virtual options, the district is categorized as Traditional.

• When different learning plans are offered by grade level, the school district weightings are proportionately assigned (i.e. if Grades K-5 are Traditional and Grades 6-12 are Virtual Only, the weighting for the district would be 6/13 or 46% Traditional and 54% Virtual).

• The learning style weightings (%V, %H, %T) for each of the audited school districts with in a county are then used to generate county level learning style weightings. These weightings are done to reflect student enrollment of the county (i.e. larger districts are weighted more heavily than smaller ones).

We used three different sample groups which generate three different margins for error.

• For 232 of the most highly populated counties in the US - representing over 28% of the US student population -  Burbio samples school districts representing an average of 90% of the students in those counties - generally it's just one district - and then categorizes the type of learning accordingly. For that group of 232 counties, margin for error at 95% confidence is 0.1% given the high concentration of sampling that occurred. 

• For 228 additional highly populated counties - with multiple independent districts that in theory could make different choices about learning plans -  Burbio audits between three and ten school districts per county, focusing on a mix of small and large.  We determined  a  margin of error of 3.8% based on the sample size versus the number of districts.  This group of counties makes up 47% of the US student population. 

• For the remaining counties, (25% of student population) we audit a total of 130 school districts.  There is a margin for error of 8% in this subgroup based on sample size versus total number of school districts. 

• For overall margin of error, we took the square root of the sum of the squares in our initial populations to maintain our 95% confidence interval. The result gave us an overall error of 2.73%.