Critical Incident Technique

An incident is critical when it makes a clear, significant difference, positive or negative, to the stated aim of the activity. Flanagan's definition has two parts: the incident must be a specific, observable piece of human activity complete enough to permit inferences about the person, and it must matter to the objective, either contributing to it or detracting from it. A routine action that has little bearing on success or failure is not critical. This is why defining the general aim first is essential, because criticality is judged relative to that aim, and it is what keeps the method focused on behavior that actually distinguishes effective from ineffective performance.

Flanagan tied the number to category saturation rather than a fixed count: you keep collecting until additional incidents stop producing new behavioral categories. The number needed therefore depends on the complexity of the activity. Simple, narrow activities may saturate after a few dozen incidents, while complex jobs can require many hundreds or even thousands. A practical check is to monitor how many new categories each batch of incidents adds; when that approaches zero, the behavioral framework is reasonably complete. Reporting how saturation was judged is an important part of demonstrating the rigor of a CIT study.

It is fundamentally a qualitative method, since its core activity is eliciting and inductively classifying rich, behavioral accounts of incidents. However, it has a quantitative side: once incidents are categorized, researchers can count how many fall into each category and use those frequencies to indicate which behaviors recur. This counting should be interpreted cautiously, because incidents are sampled by salience and memorability rather than by representativeness, so category frequencies reflect what observers found striking rather than the true base rate of behaviors. Used carefully, CIT bridges qualitative depth and a modest, descriptive quantification of behavioral categories.