Multiple, small failures that align to cause an adverse event is illustrated by the "Swiss cheese model" on the right that was developed by James Reason (and is used with permission). In this model, each slice of cheese represents a small failure that is relevant to a particular incident or risk. While the model may give the impression that each slice of cheese and the location of its holes are independent, this may not be the case. Different failures may have a common failure mode. In other words, several layers of the same cheese line up. Examples of "smaller failures" that together could possibly cause a significant incident include
- Poorly designed work schedules.
- Lack of teamwork.
- Lack of staff education.
- Need of procedure revision or policy review.