Schools could see “more variation than usual” in this year’s exam results, Ofqual has warned.

In a letter sent to schools today, the exam watchdog said that changes to qualifications - with a new batch of reformed GCSEs and A levels being sat this summer for the first time - may result in more volatility in results.

“Generally, when qualifications change, we expect that there might be more variation in school and college results,” the letter states.

The letter says that last year Ofqual saw “normal levels of variation, including in those subjects that were reformed”. However, it goes on to warn: “It is still possible that some schools and colleges could see more variation than usual this year”.

Ofqual’s assessment of the situation in 2017 contrasts with that of the Association of School and College Leaders, which reported last summer that schools with “good” English departments had seen a drop in the results they achieved in the new English GCSEs.

The headteachers’ union said it had been contacted by schools who had experienced “unpredictable results”.

Different cohort

In today’s letter, Ofqual warned that results in GCSE science could be different this year because of a change in the cohort. Entries in the new double award science are higher than the total entries last year for the pre-reform science and additional science qualifications, and entries for separate sciences (biology, chemistry and physics) are also up.

“Because the nature of the cohort taking these qualifications is different from previous years, it’s likely that results this summer will look different, and schools should be careful in comparing previous results in science and additional science with 2018 results in combined science.”

Ofqual also reiterated its warning that schools should not try to predict grade boundaries because these are not set until after papers have been marked.

“We have seen many people trying to predict where the grade boundaries will be for new qualifications,” the letter says. “Please treat all such predictions with caution.”

Following a further drop in AS level entries, Ofqual said it had conducted research looking at whether “this decline had any implications for maintaining standards” in the qualification, which it will publish this summer.