(Hongqi Zhang /iStockphoto)

As parents, community leaders and school officials puzzled over the precipitous drop in standardized test scores at one of the District’s leading public high schools, Emma Buzbee had a logical explanation.

Buzbee, a senior at Wilson High School, said she and other high-performing students either refused to take the test or intentionally flubbed it to focus on Advanced Placement tests, which were given the following week.

A high score on the AP exam can strengthen a college application, earn a student college credit and exempt them from certain required college courses. The standardized test administered by the District, on the other hand, has no effect on students.

But that test, known as the Partnership for Assessment of Readiness for College and Careers (PARCC), is used to judge the performance of schools and, starting next year, evaluate teachers. Which means the PARCC exam carries high stakes for teachers and school officials and no stakes for students.

When Buzbee realized that the review session for AP chemistry at Wilson High was scheduled last spring at the same time as the PARCC exam, she felt she had little choice.

“Chemistry was such a difficult subject for me, and the AP exam is very strenuous,” Buzbee said. “Me and a lot of people in my class decided not to take the exam and go to the review instead. There was never any explicit reason we were given about why we were supposed to take the [PARCC] exam.”

Buzbee said she never intended to create problems for her school.

Federal law requires school districts to give a standardized test in math and reading to every student annually in grades three through eight and once in high school — usually to sophomores or juniors. School districts are required to test 95 percent of eligible students.

Interviews with several Wilson students and parents showed there was confusion at the school last spring swirling around the PARCC exam.

In response to complaints from public school students, teachers and parents about over-testing, school districts across the country have allowed families to “opt out” of the federally required tests.

D.C. Schools Chancellor Kaya Henderson said she could not grant requests from about 100 Wilson parents asking for their children to be excused from the tests because D.C. Public Schools (DCPS) has no such policy.

It appears some took matters into their own hands.

Ellen Leander said her son, who is now a junior at Wilson, answered a few questions on his PARCC exam and then walked out because he didn’t want to miss a chemistry lab.

“He wasn’t thinking, ‘It’s going to be a win for Wilson if I win on this test,’ ” Leander said, adding that the resulting drop in the school’s PARCC score doesn’t mean that instruction is weak or the school isn’t performing. “I’m not concerned with the quality of education at Wilson. I think it’s a strong school with great teachers.”

Despite the city not having an official “opt-out” policy, some Wilson students interviewed said they received permission to skip the test after their parents emailed school administrators.

Sophie ReVeal, a senior at Wilson, said her parents got a school administrator to remove her from the PARCC testing pool so she wouldn’t have to miss two AP English classes. She said the testing process was disorganized and confusing but shouldn’t reflect poorly on the school’s teachers and student body.

“I do feel guilty that we didn’t take it because it seems that we could have taken it and it would have helped the school,” she said. “But I do blame the school for doing a really bad job on organizing it. It was really confusing, people felt forced into it, and it just didn’t feel valuable to a lot of students and wasn’t worth their times.”

Results of the PARCC tests, released Tuesday, showed that just 21 percent of Wilson students met or exceeded expectations on the English portion of the exam, compared with 50 percent in 2015. There was a 10.5 percentage point increase in the number of Wilson students meeting or exceeding expectations in math.

At School Without Walls High School — another high-performing DCPS school where students must apply for admission — there was a 12.4 percentage point drop in students meeting or exceeding expectations on the English portion and a 24 percentage point drop in math.

On the day the scores were made public, Kimberly Martin, Wilson’s principal, said she was aware that some students rushed through the English test, spending five or 10 minutes on an exam that is designed to last at least 90 minutes.

She sent a letter to Wilson parents Wednesday pledging improvements. “We need to work on resolving some of the test administration conflicts,” Martin wrote. “We know we need to be especially cognizant of the Advanced Placement administration dates as they relate to PARCC testing.”

Asked to elaborate, Martin agreed to an interview with The Washington Post but then canceled it Thursday.

D.C. officials have been scrambling to defend Wilson and School Without Walls.

“The grown-ups are in charge of setting the tone for the students of what’s important. Our students do rational things, they had a reason for doing what they did,” said Jennifer C. Niles, the District’s deputy mayor for education. “If we didn’t create the optimal environment to succeed, that’s on us.”

This is the second year that public school students in the District have taken the PARCC exam. Unlike the previous standardized test that D.C. students took, the PARCC exams given to high school students are course-based, not grade-based.

Most of the students who took the English and math PARCC exams were sophomores. But some upperclassmen who took geometry in eighth grade were also given the PARCC geometry test, even though several had already taken the PARCC exam as sophomores.

Henderson acknowledged Tuesday that there was some confusion within the school system about which students should be tested when.

It’s unclear how many students opted out of the test or intentionally failed it. The D.C. State Board of Education said there is no way to differentiate students who were merely absent on testing day from those who intentionally stayed home to avoid the test.

The PARCC participation rate at Wilson was one of the lowest among the District’s high schools, though it remained similar to the school’s low participation rate the previous year. Just 68 percent of students who were supposed to take the test at Wilson did so, according to data from DCPS.

By comparison, Anacostia High School had a 90 percent participation rate on the English portion on the exam.

An assistant principal at School Without Walls sent a letter to the school community before the test, acknowledging some confusion and saying that the school could not “accept any exceptions” to taking the test. The school, which has a much smaller student population than Wilson, had a participation rate above 90 percent on the English portion of the exam.