Five-year survey of masters degree students finds big audiences lead to grade deflation, with top performers suffering the most
Universities can get the best from bright students if they keep the number of people attending any one lecture to under 100, research reveals.
Lecturers from the London School of Economics and University College London studied almost 11,000 masters students at an unnamed university from 1999 to 2004.
They found that students with consistently high scores were more affected by changes in class size.
Students of all abilities who changed from a lecture with 56 people attending to one with 89 attending saw marks fall by 9% on average.
For those students in the top 10% of their year groups, the effect was almost four times this.
The research, published in the Economic Journal, found that lectures of between 104 and 211 students "significantly reduce test scores".
It says: "The highest ability students would benefit the most ... from any reduction in class sizes, when class sizes are very large to begin with."