In a case study you examine a real-life situation with all its complexities to discover what factors might contribute to outcomes.

A case study is used to study a particular situation in depth. It is not possible to generalise from the findings of a case study, but it can be used to better understand what works well and less so, and the conditions that lead to change.

The ‘case’ being studied may be an individual, organisation, service, event, or activity, existing in a specific time and place. Organisations or individuals are usually chosen for case study because they are interesting or exceptional in some way.

Case studies can be based on any mix of quantitative and qualitative evidence.

Selected methods and techniques

a)    Exploratory Case Studies. These are condensed case studies performed before starting a larger scale study. They are descriptive but aimed at generating questions and suggestions for later investigation rather than for illustrative purposes.

b)    Illustrative Case Studies. These are largely descriptive. They typically use one or two instances of an event to show what a situation is like. Illustrative case studies can help to make the unfamiliar familiar and add realism and depth about a project or service.  

d)    Cumulative Case Studies. These bring together information from many case studies collected from different sites and different times. The idea is to bring together learning to help generalise about a situation or answer an important evaluation question.

e)    Implementation/Impact Case Studies. These help to explain either the implementation of a project or service or the way that it brings about results. It helps to explain relationships between particular components.


  • Helpful in showing how processes work over time and therefore provide insight into causal effects
  • Can be used to illustrate evaluation reports by giving vivid examples
  • Able to be used to provide a holistic picture of projects or services 


  • Data collected is case specific and it is difficult to make generalisations
  • Method can require substantial resources, due to the in-depth and multi-method approach
  • Often associated with promoting or showcasing best practice, or where a particular activity didn't happen as expected. Cannot be used as a replacement of other evaluative techniques


Evaluation Support Scotland has produced a straightforward guide to Writing Case Studies to support evaluation activity.  This is focused more on a way to present evaluation data rather than a data collection method. 

More in-depth information can be found in the widely cited book by Robert K Yin on Case Study Research: Design and Methods (Applied Social Research Methods).