Root and common causes of selected defects are systematically defined.
SP 1.1 Define defect selection parameters and defect classification scheme
SP 1.2 Select defects for analysis
SP 1.3 Analyse causes of selected defects
The purpose of this Goal is to ensure that not only are defects found, but there is an attempt made to reduce the introduction of them as early as possible.
This is done by going back to the root cause of where the defect originated .
It will not usually be possible for an organisation to be able to carry out root cause analysis on every defect raised. It is thus necessary to have some selection criteria by which the full set of defects can be reduced to just those that are most important to the organisation. Maybe just severity 1 defects are selected, or just those that made their way into live. Maybe just those that have the greatest impact on users or those that cost the organisation most money would be selected.
The defect classification scheme that has already been defined in the incident management process can be used, expanded if necessary.
There are many techniques that can be used in root cause analysis including:
All of these techniques help to get back to the fundamental cause of a defect being injected into a product. TMMi does not dictate which techniques to use, it is for individual organisations to decide which is the most appropriate to use for their defects.
Example Sub-practices and work products
Specific Practice 1.3 Analyse cause of selected defects
Perform causal analysis of selected defects to determine their root causes and identify common causes.
Typical work products –