This special issue developed out of a thematic seminar series funded by the ESRC's Teaching and Learning Research Programme (TLRP). It brings together commentary and scholarship on the theme of quality in education research, much having emerged during the seminar series itself, and some as a consequence of the activities and discussion generated.Perhaps the key underlying question is about how we can judge the quality and security of research findings.

In the series and the articles in this issue there has been reasonably common agreement about several things. The quality of research is not defined by its impact, utility or popularity. It cannot be encapsulated in a checklist of dos and don'ts. Nor can it be reliably judged by current systems of peer review. However, there remain important differences in the views expressed in this issue - differences apparently so great that it is not clear that the notion of 'quality' is itself agreed.