This is the third phase of the DMAIC process. [If you happen to land on this article and have not see the previous ones, please have a look here: “Process Improvement“].
In this phase the improvement team will analyse the process performance to understand more precisely the “pain-points” and determine (or validate) the root causes of inefficiency. Some key topics covered in this phase are:
- checking for any patterns in the measurements taken in previous phases;
- ensuring the root-causes of the problem are identified;
- investigation for areas of concentration of issues or problems;
- prioritisation for the interventions.
In the investigation of the root-causes it is important to stick to the data, the measures and the observations, and not be biased by own past experience, beliefs or opinions so to reach an evidence-based conclusion. The tools used in this phase are highly dependent of organisation’s sector, the nature of the process being investigated and scale of the process improvement initiative. Depending on circumstances, in this phase it could be possible also to do some testing with a ‘Designed Experiment’ in which some selected settings in the process are changed so to test improvement hypothesis.
Below is a selection of the tools, which are not necessarily in the order of priority or importance.
Cause & Effect (“Fishbone”)
A ’cause-and-effect’ diagram helps the team ensure that all aspects of the problem are investigated and no less-evident causes have been overlooked. It is a team exercise during which the discussion will be arranged around a visual that resembles the skeleton of a fish, hence the name as “fishbone“.
These diagrams will not tell which of the potential causes is the responsible for the pain-point or indicate key areas to improve. A selection of few causes will have to be done by the improvement team for further investigation.
“5-Y”
The “5-Y” ( also know as “5-Whys”) is meant to be one of the most effective tools for root cause analysis and one that I really like. It is quick and very easy to use especially in loosely structured circumstances , such as in casual conversations.
It is a series of questions that starts with the focused problem or area of interest and then further four “Why” questions are asked. The interviewer asks progressively more in-depth questions. It can be surprisingly insightful and reveal problem causes that may be difficult to identify otherwise.
Interrelationship diagram
This is a difficult one, but extremely powerful as it encourages to think in multiple directions (something that most of us really struggle with), rather than linearly . Once all ideas about possible causes or issues are listed, the team is asked to look for cause/influence relationships amongst all the items and draw relationship arrows. An outgoing arrow from an idea/cause indicates that it is a stronger cause of influence. An item with a high number of outgoing arrow is likely to be a root cause (or a driver). This is the item that should be looked at first.
In an interesting example presented here, the unsatisfactory productivity in a small hospital was investigated, with an analysis of different factors that could play on the ultimate performance. The interrelationship diagram (see visual next) suggests that attention should be focused on ensuring the availability of nurses, other support functions, and operational equipment. These areas show primarily outgoing arrows, indicating them as basic causes.
At the end of this phase the root causes of the problem (or the key steps to be targeted for improvement) are identified and prioritised so the improvement team will be ready for the next phase.
Marco Bottacini, Senior Portfolio Manager, GALVmed
The views and opinions expressed in this blog are those of the author and do not necessarily reflect the views and opinion of GALVmed.
Project Management Discussion Group 