Bigger class sizes have a negative impact on students' examination performance, according to a five-year study.
Academics from the London School of Economics and University College London analysed the final exam marks of full-time students enrolled on a one-year master's programme at a UK university. They found that class size matters for student performance, particularly for the most able candidates.
The research, published in The Economic Journal, provides "some of the first estimates" of the impact of class size on university students' academic achievement as measured by their end-of-year test scores, say the authors, Oriana Bandiera, Valentino Larcinese and Imran Rasul.
"There is robust evidence of a negative class-size effect - on average, larger classes reduce students' academic achievement," they write.
They conclude that reducing the size of very large modules with more than 100 students could be a cost-effective way to improve standards.
A study by Graham Gibbs, former head of the Oxford Learning Institute, published in September, examined research spanning three decades. It concludes that measures of "educational process" including class size, teaching staff, the effort students make and the feedback they receive are the best predictors of good-quality education.
Professor Gibbs argues that such data should be published if ministers want higher tuition fees to reflect the educational quality of courses rather than universities' reputations.
However, plans for a new set of information that will be published about every university course do not include data on class sizes.
Meanwhile, a survey of academics has revealed the trials and tribulations of university teaching, including lecturers' concerns about the threat of redundancy.
Academics are keeping monthly diaries about their working lives as part of Share, a research project led by the University of Kent, which is investigating teaching practice.
In the latest project newsletter, one lecturer writes about "the increasing terror that the job I trained eight years to do and lived on the breadline for may be taken away from me".
Another says: "I had thought research was the way to build a career, but we have been told that there is no money in research and we must concentrate on teaching because that is the way to ensure there are no compulsory redundancies."
Others speak about their frustrations over the lack of time for preparation before lectures and classes.
"I find it intensely frustrating that nobody seems to think that development of material for teaching should be allocated any more than the merest token of time," one diarist writes.
Academics also talk about their disappointment at poor exam results.
"I was on a two-day vacation, came back and checked 35 exams only to realise that the students did not understand me," writes one.