There is some evidence that parents of children at grade 6, 7 and 8 who are doing poorly on academic grades lose the financial support of parents and drop out of school.
Most of the controlled assessment work was submitted in the summer and when examiners saw evidence of over-marking, exam boards raised grade boundaries, leading some pupils to receive poorer grades than expected.
"It is not correct to say that AQA adjusted grade boundaries more than other exam boards and we are not aware of any evidence that would support this view, " a spokesman said.
There is also increasing evidence that interventions can produce middle-to longer-run effects on school achievement, special education placement, grade retention, disruptive behavior and delinquency and high school graduation.