Education officials in New York City are concerned that some public schools may be manipulating grades to cover up lackluster performance.
The New York Times reports that city officials informed school principals Friday that they would implement a new auditing system to double-check standardized test scores, reported graduation rates and grading practices.
The move comes after observers noticed that high numbers of students were being given the minimum score on state Regents exams.
That has raised suspicions that some teachers may be giving their pupils a higher grade than they deserve to prevent them from flunking.
City officials have said they do not believe grade inflation or test manipulation is widespread.
New York has the nation's largest public school system.