Clinical observations: case studies. Case studies in clinical medicine involve a detailed account of careful clinical observations, taking the personal history of the patient in relation to the illness, describing the symptoms, diagnosis, treatment(s), and the outcome of the treatments. Within a psychological context, case studies might be relevant to psychotherapy or counselling. Otherwise, they might be drawn from a medical setting, involving psychiatric or neurological observations. The term case study has now been generalised to include very detailed, tightly focused descriptions of single individuals, which might contain both 'inside' and 'outside' data (i.e. the viewpoints of both the researcher and the person being researched). Unlike experiments, which tend to focus on a single moment in time, case studies usually provide a summary over a period of time (cf. longitudinal studies). The main focus is usually qualitative, though some include quantitative aspects. Case studies have proved invaluable in the study of child language development and chimpanzee language. Comparing case studies from a range of different people can provide information about: treatment outcomes, the classification of different clinical disorders, and the basis for developing new theories about particular clinical or social phenomena.