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Control Change Cause Analysis (3CA) is a method for analysing the individual, cultural and management system causes of incidents.

3CA - Control Change Cause Analysis

Investigators can use 3CA to analyse the root causes of any type incidents of any type. The first step is to identify events that compromise control or increase risks significantly. Each of these significant events can form the subject of a 3CA analysis. 3CA is available in three forms: A, B and C.


3CA has its origins in a co-operative project run by Humber Chemical Focus and the UK Health & Safety Executive (HSE) in 2000.  The A-form of 3CA (and its worksheet) was designed to be quick to learn, systematic, and to produce transparent results that are easy to communicate.

During 2007-8, NRI worked with the UK Health and Safety Executive to revise the original 3CA materials; this work produced the B-form of 3CA and a new worksheet. The two forms of 3CA are equivalent in terms of function; they perform the same analytical tasks. The differences between the two forms of 3CA are described in appendix 3 of the 3CA 'Form  B' manual.

In October 2009, the authors introduced a graphical approach to 3CA analysis. This began as a training prop and, as it proved effective in the field, was written-up as a the C-form of 3CA. The C-form can be used with a paper-and-pencil worksheet, or with a MS Word worksheet which also acts as a quick guide.