Does attending lectures improve student performance? Using novel attendance data, we examine statistically the relationships between attendance and performance for first-year and third-year students. The relationship is moderately positive: very high attendance is significantly associated with an improvement in performance over very low attenders of between 5.3 and 12.8 per cent, depending on circumstances. Then, we provide qualitative evidence from in-depth interviews with students about their views and motives regarding lectures. We find a range of reasons why attendance may be less than complete, and conclude that attendance is related to performance in complex ways. (Contains 1 figure, 2 tables and 11 notes.)