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  • It can provide a convenient way of assembling facts from the investigation, which avoids mislaying or overlooking evidence and consequently can, in the hands of a good investigator, produce a better report in less time. 
  • It enables the Tripod Beta tree to be drawn with no graphic design skills.
  • Developing the tree as the investigation progresses aids understanding within the investigation team and, including a well-drawn completed tree in the final report, aids understanding for all those who read the report.
  • Most software packages have prompts and reminders so you are less likely to overlook points or sections in the report.
  • Error alerts can highlight omissions or illogical relationships as the tree is being constructed and, as a consequence, reduces the time spent on proof reading and correcting.
  • It can automatically format the data into a concise report. For those who have "writen-up" the notes from an investigation team will realise how much time this can save 
  • A consistent layout is a significant help to senior managers who, in the course of a year, may be required to read many incident reports.


  • Cost of software, IT support and training.
  • It takes time to become familiar with the software so it is unlikely for the whole team to be competent in using it; hence the responsibility for producing the report will probably be left to one person.
  • A projector is needed to display the tripod beta tree onto a screen throughout the analysis phase to keep the whole team engaged. 


  • Using Microsoft Word to write a novel does not guarantee a best seller. Similarly using accident investigation software does not necessarily produce better reports. If the investigation team cannot produce a good report using a flip chart and post-it notes then they are unlikely to produce one using software.
  • The software can be more of a hinderance than a help for those who are not familiar with it.

Software packages that are aligned with the Tripod Beta methodology are:


Tripod Beta Version 4

Advisafe have pooled their development resources with other providers and now, in addition to maintaining the original Tripod Beta software, also fully support the further development of investigator 3.


Investigator 3 (i3)

A KelvinTopset / Governors product – they work closely with the Stichting Tripod Foundation to keep the software aligned with current developments in the methodology.

A 30d free trial is avialable - please contact us and we will forward your request.

File size 27.3 MB


Investigator 3 – software manual and training guide


63 pages



BSCAT links the bowtie concept to DNV’s incident investigation methodology -Systematic Cause Analysis Technique.



ICAM draws on the work of Professor James Reason and incorporates best practice Human Factors and Risk Management principles

SWS ICAM incident reporting

Safety Wise Solutions

An ipad app.

It facilitates the reporting, information gathering and investigation of workplace incidents using the ICAM Investigation Model.

Go to the link for a video on its use

Tripod Beta diagram symbols for use in powerpoint

A stencil is a set of objects that you can select and drop into your own diagram.

It will help you to produce reasonable diagrams quickly.

You will need Microsoft PowerPoint application installed on your computer.

Download either the ppt (1997 – 2004) or pptx (2004 – present) version.

Open the stencil file alongside the file that you are working on and select, drag and drop objects from one to the other.

Click on the text area to add text.

You can also drop these symbols into Visio and Graffle.


Note that there is a place to number each element - useful when linking to text in a report or in group discussions.


One major user of Tripod Beta is combining the findings from many reports by producing histograms and trends of immediate causes. To record the necessary information on the diagram, a two digit code can be added to each Immediate Cause. 


The human behaviour types are grouped into three categores; Skill based errors (S), Mistakes (M), and Violations (V).


Sub divsions of these three categories become: Slip - SS, Lapse - SL, Rule based mistake – MR, Knowledge based mistake – MK, Routine violation – VR, Situational violation – VS, Exceptional violation - VE, Optimising for company violation – VC, Optimising for personal gain violation – VP, and Reckless violation - VK.



Sequentially Timed Event Plot (STEP)

Blank cards for drawing sequentially timed event plots (STEP)

Print directly from the powerpoint file or cut and paste into another file format.


Histogram of occurrences of BRF Categories

Arrange the open stencil file alongside the file that you are working on and drag and drop objects.

Click on each element in turn to adjust height.


Bow Tie diagram

Arrange the open stencil file alongside the file that you are working on and drag and drop objects.