ABSTRACT
There are several types of case study. Yin (1984) identifies three such types in terms of their outcomes: (i) exploratory (as a pilot to other studies or research questions); (ii) descriptive (providing narrative accounts); (iii) explanatory (testing theories). Exploratory case
studies that act as a pilot can be used to generate hypotheses that are tested in larger scale surveys, experiments or other forms of research, e.g. observational. However Adelman et al. (1980) caution against using case studies solely as preliminaries to other studies, e.g. as preexperimental or pre-survey; rather, they argue, case studies exist in their own right as a significant and legitimate research method. Yin’s (1984) classification accords with Merriam (1988) who identifies three types: (i) descriptive (narrative accounts); (ii) interpretive (developing conceptual categories inductively in order to examine initial assumptions); (iii) evaluative (explaining and judging). Merriam also categorizes four common domains or kinds of case study: ethnographic, historical, psychological and sociological. Sturman (1999: 107), echoing Stenhouse (1985), identifies four kinds of case study: (i) an ethnographic case study – single in-depth study; (ii) action research case study; (iii) evaluative case study; and (iv) educational case study. Stake (1994) identifies three main types of case study: (i) intrinsic case studies (studies that are undertaken in order to understand the particular case in question); (ii) instrumental case studies (examining a particular case in order to gain insight into an issue or a theory); (iii) collective case studies (groups of individual studies that are undertaken to gain a fuller picture). Because case studies provide fine grain detail they can also be used to complement other, more coarsely grained – often large-scale – kinds of research. Case study material in this sense can provide powerful human-scale data on macro-political decision making, fusing theory and practice, for example the work of Ball (1990), Bowe et al. (1992) and Ball (1994a) on the impact of government policy on specific schools. Robson (2002: 181-2) suggests that there are: an individual case study; a set of individual case studies; a social group study; studies of organizations and institutions; studies of events, roles and relationships. All these, he argues, find expression in the case study method. He adds to these the distinction between a critical case study and an extreme or unique case. The former, he argues, is:
when your theoretical understanding is such that there is a clear, unambiguous and non-trivial set of circumstances where predicted outcomes will be found. Finding a case which fits, and demonstrating what has been predicted, can give a powerful boost to knowledge and understanding.
