Extreme or deviant case sampling: an essential way to learn from both success and failure

This website blog explains the lessons that can be learned from extreme case sampling and why you should take notice of "outstanding successes" and "notable failures" especially when you have limited resources and time.

Extreme or deviant case sampling means selecting cases that are unusual or special in some way, such as outstanding successes or notable failures.

Excerpt

"The highly influential study of high performing companies In Search of Excellence (Peters & Waterman 1982) demonstrates the logic of purposeful, extreme group sampling. The sample of 62 companies was never intended to be representative of US industry as a whole but rather was purposefully selected to focus on innovation and excellence.

In the early days of AIDS research when HIV infections almost always resulted in death, a small number of cases of people infected with HIV who did not develop AIDS became crucial as they provided important insights into directions researchers should take in combating AIDS.

If you use extreme case sampling you can learn lessons about unusual conditions or extreme outcomes that are relevant to improving other, more typical projects or programmes." (Laird 2012)