Administrative data are data derived from information routinely collected by organisations, such as school exam results or general practitioner health records. Administrative data offer social science researchers different sources of quantitative data that can potentially open up new research into the interactions between people and organisations and on social phenomena that may not be amenable to other forms of data collection. This entry focuses on the analysis of “structured” administrative data, being databases of mainly quantified data, and is split into two sections exploring why a study might choose to draw on these data, and how they can be analysed successfully. Internationally, improvements in technologies and investment in research infrastructures are gradually improving access to administrative data. However, regardless of how data are accessed, an important step in analysing administrative data is the process of understanding its socially constructed origins within organisational processes to assess the fit of the data to the research goals.