Methods
Critical Incident Technique (CIT)
Facts:
Also called: Critical Incident Study
Lifecycle stage: Requirements, Evaluation
Version: 11/2005
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.
The method generates a list of good and bad behaviors which can then be used for performance appraisal.
- Basic Description
- How To
- Special Considerations
Benefits, Advantages and Disadvantages
Benefits
CIT identifies possible sources of serious user-system or product difficulties. The recommendations for improvement try to eliminate the potential for the same situation to result in similar loss. However only actual use demonstrating that the product no longer induces the problem ensures that it is currently safe.
Advantages
- Flexible method that can be used to improve multi-user systems.
- Focuses on important issues e.g. safety critical events, so may bring major benefits.
- The CIT is useful for identifying rare events that might not be picked up by other methods that focus on common or everyday events.
- Can be applied using questionnaires or interviews.
- Useful when problems occur but the cause and severity are not known.
Disadvantages
- It focuses on critical incidents therefore:
- routine incidents may not be reported
- it is poor as a tool for general task analysis
- The method can be used in situations where you cannot observe behavior because of hazards, security, or privacy
- Since critical incidents often rely on memory, incidents may be distorted or even forgotten if the incident is collected long after an event.
Cost-Effectiveness (ROI)
This can be very high as the study may result in major problems or loss being addressed and future losses reduced as a result of the study.
Read More About It
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.
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.
