Before revision: In the early days of the Swiss cheese model, late 1980 to about 1992, attempts were made to combine two theories: James Reason's multi-layer defense model and Willem Albert Wagenaar's tripod theory of accident causation.
After revision: In the early days of the Swiss cheese model, late 1980 to about 1992, attempts were made to combine two theories: James Reason's multi-layer defence model and Willem Albert Wagenaar's tripod theory of accident causation.