What is a case study?

A case study is a type of research study that focuses on a single individual or group in-depth, usually to explore an interesting observation, medical issue, or event. 

What is the purpose of a case study?

A case study helps researchers and practitioners explore a particular phenomenon or condition more closely in the real-world setting. Case studies are considered a type of descriptive research, meaning they help describe something that occurs at one point in time. They help scientists generate hypotheses regarding determinants or factors of a condition or disease. These hypotheses are then tested further in experimental research designs.

What are strengths and limitations of a case study? 

Case studies can be particularly useful when studying a unique or rare disease where large sample sizes are unavailable. They also allow for researchers to collect a richer, deeper content of data that may not be feasible in other study designs. However, it is important to remember that a case study is a type of descriptive research that is observational. Because of this, case studies are limited to only establishing associations among factors. An association simply means there is a general relationship between two or more variables. In order to establish a causal relationship (meaning one variable causes the other to change in some way) an experimental study, such as a randomized controlled trial needs to be done. 

What is the difference between a case study and case-control study? 

Although case study and case-control study sound similar they are different in scientific rigour. A case study is a type of descriptive study whereas a case-control study is a type of analytical study. While a descriptive study describes an observation, an analytical study tests a hypothesis. An analytical study has the power to prove cause and effect, whereas a descriptive study does not. A case-control study compares two different groups to study how they differ, whereas a case study does not have a control group to compare with.