ODC: Orthogonal Defect Classification

Ram Chillarege proposed a technique in the early ’90s called Orthogonal Defect
Classification (ODC), as a way of categorizing defects found both during the
development process and after customers receive and begin using the product.


In ODC, defects are classified according to key attributes and then data are
analyzed to form the basis for action plans and process improvement activities.
ODC is a technique mid-way between the traditional RCA (more qualitative and timeconsuming)
and Statistical Defect Models (more quantitative, but not easily translatable into corrective action).
Through the orthogonal classification of defects found (defect type) and their association with their trigger, it is possible to create consistent and meaningful characterizations of the problems that are found across all software development life cycle stages.

A list of strengths and possible limitations in applying ODC has been compiled from the
literature:

Strengths:
o It is an evolution of RCA from a qualitative to a quantitative approach.
o It has adopted a standard taxonomy (types; triggers), which allows
comparability across time and organizations.
o It helps in gathering defect data over time, enabling an organization to run
statistical analysis and – more generally – to look at defect data in a more
objective way.

Limitations:
o It is challenging to use Software Defect Removal, since a large part of the SPI
activity is focused on the code. Furthermore, the later a generic defect (not only
code) is detected, the more difficult and costly it is to remove [12].
o It is typically applied by organizations having a robust measurement system: ODC
needs the capability to consistently gather and analyze data over time; a number of
organizations are at lower maturity levels and do not have this capability, or the
payback period is too remote for its application to be economical.
o The updating of defect types and related defect triggers makes it difficult to
maintain a backward comparability of source defect data over a long period of
time.

Reference: Introducing Root-Cause Analysis and Orthogonal Defect Classification at Lower CMMI Maturity Levels by Luigi Buglione and Alain abran.