TYPES OF CASE STUDIES

Illustrative Case Studies are descriptive; they utilize one or two instances to show what a situation is like. This helps interpret other data, especially when there is reason to believe that readers know too little about a program. These case studies serve to make the unfamiliar familiar, and give readers a common language about the topic. The chosen site should be typical of important variations, and contain a small number of cases to sustain reader's interest.

There are pitfalls in presenting illustrative case studies. They require presentation of in-depth information on each illustration; there may not be time on-site for in-depth examination. The most serious problem is with the selection of instances. The case(s) must adequately represent the situation or program. Where significant diversity exists, it may not be possible to select a typical site.

Exploratory Case Studies are condensed case studies, undertaken before implementing a large-scale investigation. Where considerable uncertainty exists about program operations, goals, and results, exploratory case studies help identify questions about uk essays dissertation, select measurement constructs, and develop measures; they also serve to safeguard investment in larger studies. The greatest pitfall in the exploratory study is prematurity: the findings may seem convincing enough to be released inappropriately as conclusions. Other pitfalls include the tendency to extend the exploratory phase, and inadequate representation of diversity.

Critical Instance Case Studies examine one or a few sites for one of two purposes. A very frequent application is the examination of a situation of unique interest, with little or no interest in generalizability. A second, rarer, application entails a highly generalized or universal assertion which is called into question, and we can test it by examining one instance. This method is particularly suited for answering cause-and-effect questions about the instance of concern. The most serious pitfall in this application is inadequate specification of the evaluation question. The importance of probing the underlying concerns in a request is crucial to the appropriate application of the critical instance case study.