Why is it so hard to predict an A level Grade?

In the papers recently, we were told that only about half of all predictions for A Level grades are correct. According to a survey, some are overoptimistic whilst others underestimate what their students can achieve.

Not all teachers are equally incorrect in their predictions: Independent school teachers were the most accurate in predicting the right grade, followed by grammar schools, academies, sixth form colleges and comprehensives. The lowest level of accuracy was for teachers in further education.

There may be a number of reasons for this – as a former comprehensive school teacher I can think of a few. In my personal circumstances, my subject, History, was an option subject, not a compulsory one. Yet, a History GCSE was not a necessary precursor to A Level History. I also took on  students that achieved good grades in RE and English as the transferable skills are similar. Mostly essay-based subjects such as Humanities are classed as equal. However, there are some key skills essential to History, like interpreting historical picture sources that those students may be unfamiliar with. The predicted grades are based on previous achievements. Clearly, then, in this case there are no previous History achievements to record, making an accurate prediction much harder.

Moreover, I faced A Level classes just shy of 20 students. Speaking to colleagues from independent schools, their classes were about half the size, posing the questions: how well do you get to know your students and how good can your support really can be with the first exams looming after only 4 months?

Also, after having completed 11 years of formal education some students simply run out of steam. Lessons remain unattended, homework not handed in and coursework incomplete. This can happen to any student, regardless of their ability, leaving the teacher with unattainable predicted grades. Perhaps this also explains why A and B grades are mostly overpredicted as was found by UCAS in their 2011 study.

However, while this addresses generally why it may be harder for some centre-types, such as UCAS classes, to accurately predict grades, it does not account for regional discrepancies. Different areas within the UK are good at spotting a specific grade. According to their findings, the areas where students perform better also predict the grades more correctly. Other variables such as ethnicity also influence predictions, posing yet another question: Do we simply expect certain students to do well and become blinkered in predicting their grades?

One thing is certain: the fact that the predictions are often incorrect is investigated nearly every year by a different institution, but despite this being communicated to the public, accuracy has not increased.