When State Commissioner MaryEllen Elia announced this year’s state test scores, she said she wasn’t sure exactly what caused such a big statewide bump — nearly 7 percent in English proficiency and 1 percent point in math.

“We cannot pinpoint exactly why the test [scores] increased,” she told reporters on Friday afternoon.

Her comments immediately turned the spike in scores into an education-world Rorschach test, and everyone saw something different in the inkblot. Mayor Bill de Blasio immediately claimed victory for the city’s almost 8 percent increase in English proficiency, while charter school advocates zeroed in on the even bigger increase in charter test scores, and researchers rolled their eyes, pointing out that test scores are an unreliable marker of progress — especially when the tests themselves have changed.

So who’s right? The answer likely involves some combination of student learning and test tweaks. We’ve compiled a list of the most prominent theories and looked at the evidence for each.

The de Blasio reforms are working

City officials wasted no time claiming de Blasio-era reforms drove the rise in test scores.

“A lot is changing, and this is pure, hard evidence that these changes are working, and we expect a lot more to come,” said de Blasio at a Monday press conference. He cited his “Renewal” program for struggling schools; his administration’s support of community schools, which offer additional services to families; and his universal pre-K push.

De Blasio’s case is supported by the fact that city proficiency rates increased more, on average, than test scores statewide. While the percentage of students passing state English scores increased by 6.6 percent, the city’s increased by 7.6 percent. Commissioner Elia also gave the city kudos, saying a renewed focus on teacher training and writing might explain the jump in scores.

State tests got easier

Could de Blasio-era reforms explain the entire increase in test scores? Probably not.

State tests across the state went up significantly — so much that Elia herself cautioned this year’s test scores are not an “apples-to-apples” comparison to last year’s. In response to the backlash over the introduction of Common Core-based assessments, officials made a number of changes to the tests this year, including shortening them and giving students unlimited time. Researchers said those changes likely explain some, if not much, of the statewide increase.

The increases “are sufficiently large that it makes me think there’s something about the difference in the tests from last year that accounts for the difference in growth,” said Aaron Pallas, a professor of sociology and education at Teachers College at Columbia University.

Charter schools are part of the answer

Just as quickly as Fariña and de Blasio celebrated the rise in scores, charter school advocates — frequent rivals of de Blasio — jumped in with their own good news.

City charter school English proficiency rate went up by 13.7 percent, beating the city’s overall average increase by a fair margin. Success Academy CEO Eva Moskowitz dismissed the rising scores at traditional district schools since they mirrored the state’s more closely and could thus be explained by the test changes, she argued. To “find real improvement,” she wrote in the New York Daily News, officials should look to charter schools instead.

New York City charter schools’ scores are analyzed separately from district schools, and so the charter growth didn’t contribute to — or account for — the city’s bump, state officials said. But their scores did contribute to the statewide increase.

The Common Core is working

There might be other explanations, but here’s the last one we’ll explore: The Common Core is working.

In 2013, state officials implemented tests aligned to the more rigorous Common Core learning standards. Experts knew the new tests would likely cause an immediate drop in scores, but officials hoped that over time, students and teachers would adjust to the new material and eventually test scores would rise.

Could this be a sign they were right? One piece of evidence to support that theory is the fact that the biggest increases in English proficiency were among third-graders, who started their elementary school education with a Common Core curriculum. Third grade proficiency levels in the state increased by 10.9 percent.

That did not go unnoticed by the Education Trust, a nonprofit that heralded the progress on state tests as a sign that higher standards work.

“The Common Core state standards and tests have been unfairly demonized and used to excuse the failures of our education system,” two leaders of the group wrote. “When we truly listen to what teachers, parents and students are saying, we know that high standards, implemented well, enable students to thrive.”

In the end, it’s likely too early to know exactly what drove the results, said Pallas, the Columbia testing expert. He is trying to isolate how much of the change has to do with test structure, as opposed to better instruction or learning. Right now, he said, parsing the two is tricky.

“There’s just too many moving parts right now,” he explained. “We’ll be able to have a better sense of what’s going on [eventually], but right now we’re in this gray area.”