Methods

Critical Incident Technique

Facts:

  • Also called: Critical Incident Study
  • Lifecycle stage: Requirements

Critical incident technique is a method of gathering facts (incidents) from domain experts or less experienced users of the existing system to gain knowledge of how to improve the performance of the individuals involved.

The critical incident technique (CIT) is used to look for the cause of human-system (or product) problems to minimize loss to person, property, money or data. The investigator looks for information on the performance of activities (e.g. tasks in the workplace) and the user-system interface. Both operators and records (e.g. documented events or recorded telephone calls) can provide such information. The investigator may focus on a particular incident or set of incidents which caused serious loss. Critical events are recorded and stored in a database or on a spreadsheet. Analysis may show how clusters of difficulties are related to a certain aspect of the system or human practice. Investigators then develop possible explanations for the source of the difficulty.

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Originators/ Popularizers

Flanagan, J.C. 1954. The critical incident technique. Psychological bulletin, 51(4), 327-358. Flanagan was first to describe the critical incident technique.

Chapanis, A. (1959) Research techniques in human engineering, John Hopkins Press, Baltimore: Maryland.

Ramsey (1977) Accident sequence model.
(Includes: perception of hazard, cognition of hazard, decision whether or not to avoid hazard, ability to avoid hazard and luck).

Authoritative References

Christensen, J. (1985). Human factors in hazard risk evaluation, Human Factors Engineering: Engineering Summer Conference, University of Michigan: Ann Arbour, Michigan.

Nemeth, C. P. (2004). Human factors methods for design - making systems human-centered, CRC Press.

Reason, J. (1990). Human error. Cambridge University Press: New York.

Published Studies

Nemeth, C. P. (2004) Human factors methods for design - making systems human-centered., CRC Press.
Report case where invasive surgical procedure performed in a hospital catheterization laboratory present the potential to inflict serious trauma on the patient. Problems were found in the possibility of contrast dye introducing air bubbles into the patients bloodstream which could affect the nervous system or brain.

Casey, S. (1998) Set phasers on stun: and other true tales of design, technology, and human error, Santa Barbara: Aegean.
Contains 20 short stories in the book covering situations from the accidental launching of a rocket to some horrific accidents in hospitals, illustrating how quickly and easily catastrophes can happen.

Related Subjects

  • Task analysis: CIT might be a complementary technique when asking domain experts to describe the tasks they perform.
  • Error analysis: Here a sample of users is observed when using a product to determine all of the errors that individuals might make while using it.
  • Group Interviews: Flanagan (1954) describes a group interview approach where people are asked to respond to a particular question using a critical incident form. This method is used when time and personnel are limited.