Chapter 6 shows how it is possible to use demographic metadata to study identities in health-related corpora. We present two case studies, based on research on patient feedback on NHS services in England. The first study compares how cancer patients of different age and sex groups evaluate healthcare services and, specifically, how they use distinct linguistic and rhetorical strategies to do this. The corpus was encoded with demographic metadata which allowed the researchers to explore the language used by people of different age and sex identity groups. For the second study, a different corpus of more general patient feedback was used, one which did not contain demographic information metadata. Instead, targeted searches were used to identify patients’ demographic characteristics based on cases where they made those characteristics explicit within their feedback. In contrasting these case studies, we also evaluate the two different approaches taken, considering the affordances and limitations of both. Taken together, the case studies demonstrate how language and identity can be explored in corpora with and without reliable demographic metadata.