DMAIC: Define, Measure, Analyze, Improve, Control

Improve anything measurable using DMAIC. The five steps are:

  1. Define: Clearly define what you will improve, the more specific, the better.
  2. Measure: Can your problem/opportunity be measured? If not, find a way.
  3. Analyze: What are the top causes behind poor performance?
  4. Improve: Implement the changes that will make the biggest difference.
  5. Control: Verify and sustain the results.
The Five Steps

Example #1 – Faster Sales Quotes

In above case, sales quote processing time was improved using DMAIC along with some lean tools and simple technology.

Notice that all of the tools used were very straightforward, things like voice the customer, process flow charts, the 8 Wastes of Lean, and Pareto charts.

It all started with a specific goal that was validated with the customer: generate all sales quotes within 24 hours of the customer meeting.

Example 2 – Eliminating Product Recalls

The above case shows how DMAIC can bring structure and confidence to an otherwise, “do your best and hope for the best” approach.

A chemical company had experienced product recalls and wanted no more recalls.

With DMAIC and the PFMEA tool, a risk metric was developed and acted upon. Zero recalls occurred after the project was completed, and the team had a proactive risk metric that was continuously improved upon.

Example 3 – Improving Website User Experience

The above case relates to improving user experience on a website.

The first question is of course, how to measure user experience. In this case a metric known as bounce rate (the % of cases where a user exits without visiting another page) was used.

Different layouts were testing using hypothesis tests, until the optimal layout was identified.

Career Development – Core Skills and Technical Skills

5 Core Skills

There are five skills/traits that are essential for anyone practicing continuous improvement and leadership in general.

These come first, before Lean, Six Sigma, or any other discipline:

  1. Facilitation is a make-or-break skill for anyone in a quality / continuous improvement role.
  2. Analysis. The ability to analyze data and find actionable information is another core skill. Most or all of this work can be done in Excel.
  3. Results-driven. If you are focused on getting results, it will come through in all of your interactions with people, and they will be more likely to support you.
  4. Relationship building. As continuous improvement professionals, we are often the least knowledgeable person in the room about a given topic. It takes strong humility and a great deal of respect for others to get things done.
  5. Communication. Frequent, concise communication keeps projects on track.

Once the above skills are mastered at a basic level, they can be used to apply Lean, Six Sigma and other skills as needed, always following the DMAIC framework.

17 Six Sigma Skills

Six Sigma is about eliminating defects/errors, and the following grid shows these tools, their level of complexity, and frequency of use in a typical lean, quality, or other continuous improvement role:

If you are new to Six Sigma and are overwhelmed, there is some good news:

Only a handful of the 17 tools are used in most projects, and those tools are the easiest to understand.

10 Lean Skills

Lean is about speeding up processes through waste elimination and other methods: delivering what the customer deems as important, with zero waste.

Lean identifies and removes waste, also known as non-value-added activities. Just like Six Sigma projects, lean projects should also be structured inside the DMAIC framwork.

Manufacturing Project Example

The example below follows an outdoor furniture manufacturer’s warranty improvement project.

Step 1 – Define

Here is the project charter. Note the specific metric and goal: reduce the warranty rate on the Cedar Essentials product line by 50%, specifically from 2.6% to 1.3%.

Project benefits include lower costs through reduced warranty returns, and increased sales via better product reviews.

Here is the project charter Excel file if you would like to use it.

Step 2 – Measure

The team put together a baseline trend chart, along with Pareto charts showing warranty rates by product type and sales channel.

Three things came out of this effort that would direct the team’s focus to the biggest opportunities –

  1. Something happened in production week 48 that spiked the warranty rate on the AD (Adirondack) chairs.
  2. The AD chairs had the highest overall warranty rate, followed by the folding side tables.
  3. The biggest clue came from the sales channel warranty Pareto – direct-ship deliveries had seven times the warranty rate of retail sales locations.
DMAIC Project - Trend and Pareto Charts

Knowing that the AD chair line would receive plenty of focus, the team went ahead and documented the manufacturing process flowchart:

Process Flowchart - DMAIC Project

A returned-product analysis showed a cracking condition on the AD chairs, and the the engineering team found excessive screw torque during assembly to be the cause.

Knowing that the screw torque variation would need to be controlled, the team first ran a Gage R&R study on the torque measurement.

The initial GR&R results showed that the screw torque measurement method was causing too much variation.

Poor GR&R results on screw torque measurement

Using a graphical technique learned in Gage R & R training, the team finds that the first operator in the study was recording consistently higher readings than the other two operators –

DMAIC Team GRR Graphical Analysis

Finally, after correcting operator #1’s measurement technique and updating the measurement procedure, the team conducts a follow-up Gage R & R study with much-improved results –

Follow-Up Gage R & R Study

Finally, the baseline sigma level for the overall defect rate is estimated  using a sigma conversion chart, providing a relative indicator of how close the current process is to delivering zero defects.  

A Six Sigma process has a sigma level of six, and for all practical purposes is considered a defect-free process over the long run, provided that adequate controls are in place to maintain capability.  

In the example above, an overall defect rate of 2.6% reflects a sigma level of 2.1.

Step 3 – Analyze

In most cases there will be no more than three causes that must be controlled in order to achieve success – if too many causes are identified, then the team has either not isolated the primary causes or the project goal is too ambitious to achieve success with a single project. 

The Analyze phase deploys a number of tools for collecting team input and experimenting to identify top causes.Not all tools are used on all projects.

In our outdoor furniture manufacturing example, the team must understand the reasons behind two of the biggest Pareto items discovered in the Measure phase:  (1) returns on the “AD Chairs” product line and (2) returns on Direct-Ship products.  

A detailed analysis via product tear-downs produced the following sub-Pareto charts, which brought the team closer the the primary causes that were driving high customer return rates –

 Sub-Pareto Charts

The sub-Pareto charts noted above further narrowed the team’s focus to (1) cracked back-slats, (2) shipping damage, and (3) missing hardware.

Step 4 – Improve

The team implemented three corrective actions that exceeded the 50% warranty improvement goal:

  1. Cracked back slats eliminated by upgrading to a more capable electric screwdriver with torque feedback accurate to 5% of AD chair design tolerance.
  2. Shipping damage on direct-ship chairs (the #1 warranty problem overall) was eliminated with some packaging improvements that ironically cost less than the original packaging that was failing.
  3. The hardware packing operation was mistake-proofed using sensors at the part bins, to ensure that operators pulled all of the correct parts for each chair.

Step 5- Control

Controls for this project included –

  1. Adding a screw-torque audit to the dock audit (back slats), until long-term capability of the new screwdriver was determined.
  2. A daily check on the error-proofed hardware retrieval process, by verifying line stoppage when one or more hardware items was missing.
  3. A Power BI dashboard was implemented to keep the weekly warranty trends in front of the team.

More Information and Downloads

The following links provide more information about DMAIC and Six Sigma.

More reading on DMAIC and Six Sigma from the American Society for Quality

Free Download – DMAIC Intro PPT

Free Download – The Statistics Behind Six Sigma

Detailed explanations of Define, Measure, Analyze, Improve, and Control