Secondary data analysis as a methodological approach is not without its critics. Indeed, three main objections to the use of secondary data analysis in social research stand out: first that because of the socially constructed nature of social data, the act of reducing it to a simple numeric form cannot fully encapsulate its complexity. Secondly, that such data is full of errors, and finally that official data in particular, is not value neutral but is controlled by those in power. This paper considers each of these objections through a secondary analysis of permanent exclusion data for all schools in England. We conclude that while existing data on permanent exclusions is not without limitations; as a methodological technique the secondary analysis of such data is an important tool for helping researchers understand the inequalities that persist in education. (Contains 1 note and 7 tables.)