The National Student Survey (NSS) of course experience satisfaction is sent to final year students of all higher education institutions in England, Northern Ireland, Scotland and Wales (N = 171,290 and 157,342 students in 2005 and 2006) and results are made publicly available. The present investigation assesses the reliability and appropriate use of the NSS from a multilevel perspective. Although NSS responses provide a limited basis for discriminating amongst universities and courses within universities, the ratings of universities are highly reliable and stable over time due to the large number of students (2005 and 2006 rankings correlated r = 0.86). The unresolved question is whether very small (only 2-3% of the variance explained) but reliable and stable differences between universities provide useful information for benchmarking universities, self-improvement, and informing student choice. (Contains 3 figures and 1 table.)