A vast number of case studies (some of which are considered classic works) is produced in academic/scientific operative research, thesis and dissertation research as well as in professional practice across a variety of traditional social science disciplines - like psychology, sociology, political science, anthropology, history and economics - and practice oriented fields such as urban planning, public administration, public policy, management sciences, and education. Case studies often occur also in evaluation research (Yin, 1989) and, quoting from Stake (1995, p. 95-6), we can even say that “All evaluation studies are case studies.” In recent years, a deep theoretical and methodological reflection on case studies produced a wide and rich scientific literature in different social research fields including economics, the most ambitious social science in its epistemological aspirations (George e Bennett, 2005). In the field of project evaluation, the extensive use of case studies is not combined with an actual awareness of its theoretical and methodological foundations or its potential as a theory-building tool and, as a consequence, some considerations on case-study as a research strategy are needed. From a methodological point of view, this presentation mainly aims at: 

• framing and defining the case-study as a research strategy (has the case-study scientific bases? What are the main features of case study? In what does it differ from other research strategies (experiment, statistical analysis, archival research, history) setting in which situations case-study is more suitable than other methods and when it is worth using it;
• proposing a definition of a case-study as a research strategy suitable for evaluation and survey;
• illustrating the main types of case-studies in the literature (e.g.: exploratory descriptive, explanatory, intrinsic, instrumental, etc.);
• presenting the case-study research design;
• highlighting the main criticisms to case-studies method (with a special, even though not exhaustive, attention to the problem of results’ generalization and validity).

From the point of view of evaluation and survey, this work aims at stimulating a reflection on the need to provide evaluative case studies with major scientific foundation suggesting the opportunity to apply a case – study research design suitable to this scientific field.