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DMAIC| Control Stage

What is it… Control is the final stage within the DMAIC improvement method. This phase is all about embedding the changes and ensuring sustainability. This is sometimes referred to as making the change ‘stick’. After all, why go through the rigorous approach of a six-sigma project if once the team go away so do the benefits!

In this phase we will standardise the improvements made within the previous Improve stage.

How long should the Control Stage take?

In theory we need to continue checking activities are working as planned and in that sense the deliverables from this stage may never end. However, depending on the type of project you are running it is feasible to expect the project element to last between 2-3 weeks.

What are the key steps… 

Step 1 | Amend Ways of Working – This can include the creation or updating of existing standard operating procedures (SOP’s);  development plans; work instructions; and process confirmation.

Step 2 | Quantify and Sign-Off Benefits – This is an all important step. We are now able to quantify the actual savings we are seeing – or anticipated to see from the changes. This is what many of the stakeholders will be seeking from the project. In some cases, this will be the only part some stakeholders actively engage within. If the benefits are going to be delivered long after the project team move on then it is important within this stage to have agreed the approach and mechanism for calculating and realising the benefit.

Step 3| Improvement Tracking – Step 2 and step 3 go hand in hand. In order to prove the benefits, cause and effect is required to be shown. Here the statistical process control (SPC) charts, KPIs and other collateral will be developed. These may be an extension of material created previously within the DMAIC cycle. It is important the before and after positions are visible so the change effect can be seen.

This step also considers what to do if things start to fall of track. We have the insight from above to know we’re going off track and developing an Out of Control Action Plan (OCAP) means remedial actions can be set in place to get back on track and minimise the damage. The OCAP should be agreed and signed-off with the owner to instigate actions based on set tolerances. If of course, these actions steps do not deliver desired results then it may be necessary to put the team back together to resolve – and as before focus on the root cause of the issue(s).

Step 4| Project Closure – Often we see this step being missed. This may sound insignificant if its ‘accepted’ that the project is complete – but if not done it can become a significant time stealer. Project members are still actively engaged and this presents reallocation of resources to other pressing problems. The closure step should follow a structured approach with approval given to close and a suitable hand over to operations or the BAU team where applicable.

Step 5| Gain Approval to close the project down and release all the resources. 



At this point don’t forget to celebrate success! And record all of those lessons learnt for future and similar projects.

At the end of the Control Stage the following will have been completed or identified: 

SOPs & Work Instructions Process Confirmation Development Plans Tracking Mechanisms Transition Plan
Benefit Delivery Glide Path Control Plan Lessons Learnt Project Report Closure Action Log

Key Deliverables of the Control Stage

  1. SOPs – Standard Operating Procedures
    1. Including Work Instructions
  2. Transition Plan
  3. Development Plans
  4. Tracking Mechanisms:
    1. Statistical Process Control Charts
    2. KPI’s
    3. Other Control Charts
  5. Benefit Delivery – Calculated with stakeholder sign-off
    1. Finance
    2. Operations
    3. Process
    4. HR


In your Closure Action Log ensure any outstanding items are documented with clear owners and dates. Though you may be tempted to jump on from the project now the same rigour must be applied at the projects close.

DMAIC Control Stage FAQ’S

What is Process Confirmation?
Process confirmation is a set approach to ensuring processes are performing as intended. A key premise of six-sigma is for processes which are repeatable, predictable, high-level of quality (minimal defects) with limited variance.

Process confirmation will often be in the form of checklist which team members, managers and leaders will use to check the process is being delivered to set standards. To be effective the approach needs to step beyond ‘ticking a box’ and cover off the following:

  1. Confirm standard work is available for the process
  2. Confirm the standard work is being deployed in a repeatable way by each member of staff
  3. Reinforce the use of set standards – i.e. praise those that consistently do and have performance discussions with those that don’t
  4. Observe any deviations and potential improvements to the standard
  5. Identify any training or skills issues for staff

This is an often overlooked part of six-sigma and lean projects but its simple in application and can have a tremendous impact on the sustainability of projects.

Done effectively it allows for reinforcement of the right behaviours and spots issues before they get out of control.

What is a Control Chart in Six-Sigma?
The primary control chart in Six-Sigma is the Statistical Process Control Chart – known as SPC. The SPC has upper control limits (UCL), lower control limits (LCL) and the mean (average). These limits are set by the spread of the data with the LCL usually 3 standard deviations below the mean and the UCL usually 3 standard deviations above the mean. 

Any data point which sits outside of the control limit lines is an outlier and if there are many of these then the process is considered to be out of control. 

SPC charts are great visual way to quickly ascertain whether or not a process is in control.  

What is the 3 Sigma limit?
The 3 Sigma limit refers to 3 standard deviations from the mean. This is a statistical calculation that is utilised with Statistical Process Control charts.
What is a Control Plan?
A control plan is developed to cover each process step and defines the measurements, specification, historical capability and a response plan.

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