This page provides access to additional resources to help practitioners understand and use Tripod Beta.
Official Tripod Beta manual
Tripod Beta: Guidance on using Tripod Beta in the investigation and analysis of incidents, accidents and business losses is the current manual on using the Tripod Beta methodology.
Download the Tripod Beta primer for a free sample of the full manual.
ISBN: 9780 8529 3728 0
Version: 5.01 (2015)
Click here to purchase this title.
Beta tree stencils: PowerPoint presentation (external
PowerPoint presentation containing blank Tripod Beta tree symbols, to enable you to create Tripod trees without using specialist software. To access, click the 'Tree stencils' tab towards the middle of the page.
Examples of preconditions and underlying causes
Annex I: Caused by... Leads to...:
A method for identifying and classifying the underlying causes of incidents, accidents and business losses
This resource is a companion to the Tripod Beta manual (Annex I). It provides 11 tables of common preconditions and underlying causes. These tables can guide the investigator on possible avenues of investigation, the level of depth expected of preconditions and underlying causes, and as a way to classify underlying causes consistently to enable multi-incident analysis.
Videos (now playable on both Widows and Apple Macs)
A collection of videos to help you understand the theory behind Tripod:
The Swiss cheese model explained - part
The Swiss cheese model explained - part 2
Movie: Explaining Human behaviour
Movie: Human behaviour theory and Tripod BetaEnglish
Movie: Human behaviour theory and Tripod Beta French
Movie: Barge incident - a Tripod Beta case study
UK P&I clubwebsite: Tripod theory (external website)
Contains excellent background to human failure and the Tripod theory. Note it uses older terminology (Hazard and Target rather than Agent and Object).
the Swiss cheese model (external website)
Shows how the Swiss cheese model has evolved over time.
Selection of incident
investigation methods (external website)
October 2009 Loss Prevention Bulletin paper that describes a number of different incident investigation methodologies. Note that Tripod Beta is the only method that covers 'what happened', 'how it happened' and 'why it happened'.
Examples of Tripod Beta investigations:
Vehicle rollover in remote desert region (external website)
Chemical plant pipe rupture (external website)
Machine operator cuts hand (external website)
Passenger accident at Brentwood station 28 January 2011 (external website)