There’s a minimum percentage that have to come from University Park and College Park. It’s really difficult to get a seat if you live outside those neighborhoods.

I have no idea what you are trying to prove.
You said they must be doing something right. My point was one of the things they are doing right is getting the student body to be more affluent. Generally speaking, a higher percentage of white kids means that the student body as a whole is more affluent.
Generally speaking, kids whose parents can figure out transportation to/from a charter are more affluent.

It also looks like the spending per pupil at CPA is higher than other schools in the county.

Spending more money + more affluent kids = higher test scores. There is no mystery to it.

It's like marveling that TAG schools are recognized as Blue Ribbon schools. If you only admit kids who are in the 80% percentile of IQ scores, most of the kids in the school are going to score high on standardized tests.

You would agree that if the school was 25 percent white and 25 percent low income than it would be number 1 in the state then!

PGCPS is 4% white so 13.5 is significantly higher.
70% of students in PGCPS qualify for free or reduced lunch and 20% of students are English language learners. ELL students still take standardized tests.

The demographics of CPA are significantly different than those of the rest of the district.

The charters only attract families who can figure out transportation. This eliminates a huge chunk of the population, especially low income or ELL students.

Really. The school is 13.5 percent white (about 675 students total) and 38 percent get free meals and 13 percent get rreduced price meals.
A few years ago ago the top 5 senior students were daughters of west African immigrants.

I think they have really improved over the years and we seriously considered it for my kids.
As far as doing something right, some of it is just demographics. The student body is vastly different than most other PGCPS schools.
They have a super low FARMS rate, virtually no ESOL/multilingual learners or students with IEPs. It is probably the most affluent and whitest school in PGCPS.
If kids are struggling, they "council them out" to their boundary school.
Easier to get great stats when you are only servicing high performing kids.

Also #23 in the DMV https://www.usnews.com/education/best-high-schools/maryland/districts/prince-georges-county-public-schools/college-park-academy-200388

Pretty impressive climb, they must be doing something right.