Monday, 29 December 2014

Root Cause Analysis For Agile


Overview

Agile typically uses Root Cause Analysis techniques drawn from LEAN.

Root Cause Analysis using the 5 Whys

The 5 Whys is a technique developed by Sakichi Toyoda at Toyota as part of the lean methodologies that were developed there. It is an iterative question-asking technique. The primary goal of the technique is to determine the root cause of a defect or problem.

The technique starts with a statement of the problem, then the application of 5 "whys", with each answer triggering the next "why".

The classic example given to illustrate this technique is:-

The problem: The vehicle will not start.

1.Why will the vehicle not start? - Because the battery is dead. (first why)
2.Why is the battery dead? - Because the alternator is not functioning. (second why)
3.Why is the alternator not functioning? - Because the alternator belt has broken. (third why)
4.Why is the belt broken? - Because the alternator belt is well beyond its useful service life but has not been replaced. (fourth why)
5.Why has the belt passed its useful service life but not been replaced? - Because the vehicle was not maintained according to the recommended service schedule. (fifth why, a root cause)

The use of 5 questions derives from an empirical observation that 5 is typically the number of iterations required to establish a Root Cause of a problem. In practice, the number may be greater or smaller than that.

Root Cause Analysis using Fishbone Diagrams



Note that a Root Cause may not be just one factor. In Complex Adaptive Systems it is common for the Root Cause to be an interaction of factors. The primary technique used to address this level of complexity is the fishbone (or Ishikawa) diagram although a tabular format listing causes can also be used. These tools allow for analysis to be branched in order to provide multiple root causes.

 Th Fishbone Diagram divides the causes into general categories (often Equipment, people, process, materials, environment and management) and iteratively explores each one in an approach similar to the 5 Whys to understand all of the factors contributing to a problem.

Note: The shapes to create these diagrams are available in Visio, in Business->Business Process->Cause and Effect Diagrams.











(Example from http://en.wikipedia.org/wiki/File:Ishikawa_Fishbone_Diagram.svg )


Mess Maps

Lean assumes some degree of linear flow. For very complex environments it may be necessary to go outside of the LEAN methodologies - a Mess Map may be required.

No comments:

Post a Comment