The Bloomberg administration will issue its final round of school progress reports Wednesday, marking potentially the end of an era in school accountability.

Mayor-elect Bill de Blasio has said he wants to overhaul how schools are assessed. He was one of several candidates to tackle the Department of Education’s letter grades, awarded annually since 2007 based on a complex algorithm that weighs students’ progress and performance relative to that of schools’ with similar students.

De Blasio and other candidates criticized the letter grades as offering too simplistic a view of school quality.

Usually, the city uses the grades to determine which schools to consider closing. This year, because the closure process would span the two mayoral administrations, no schools will be closed. But Chancellor Dennis Walcott said last week that the department would let low-performing schools know that their progress did not meet standards nonetheless.

We already have one hint about what this year’s progress reports will show. On Monday, Deputy Chancellor Shael Polakow-Suransky said at a panel event that the lowest-performing 15 percent of schools from last year — all of which received “Targeted Assistance Plans” if the department opted not to close them — had come out ahead on this year’s reports. Three-quarters of the schools with the plans saw their grades go up by at least one letter; 40 percent rose by two letters or more, he said.