Grade Expectations: How well can we predict future grades based on past performance?

The Covid-19 pandemic has led to unprecedented disruption of England's education system, including the cancellation of all formal examination. Instead of sitting exams, the class of 2020 will be assigned "calculated grades" based on predictions by their teachers. However, teacher predictions of pupil grades are a common feature of the English education system, with such predictions forming the basis of university applications in normal years. But previous research has shown these predictions are highly inaccurate, creating concern for teachers, pupils and parents. In this paper, we ask whether it is possible to improve on teachers' predictions, using detailed measures of pupils' past performance and non-linear and machine learning approaches. Despite lacking their informal knowledge, we can make modest improvements on the accuracy of teacher predictions with our models, with around 1 in 4 pupils being correctly predicted. We show that predictions are improved where we have information on 'related' GCSEs. We also find heterogeneity in the ability to predict successfully, according to student achievement, school type and subject of study. Notably, high achieving non-selective state school pupils are more likely to be under-predicted compared to their selective state and private school counterparts. Overall, the low rates of prediction, regardless of the approach taken, raises the question as to why predicted grades form such a crucial part of our education system.