🎯 Quick Answer
What: A control plan is a short written plan to sustain the gains after a project ends. It names one process owner, and it fits on one page.
The four lines: The metric. How often it is measured, and where it is posted. The process owner, and a backup. The reaction plan: what to check first if the metric goes outside its control limits.
Who owns it: One process owner, not a team. The person who runs the process every day and can act on the metric. They have said yes, they have the time, and a named backup covers for them.
The payoff: The gain from the project is still there a year later, because sustaining it is one person's job.
Most improvement projects end the same way. The result is good. The team shows it to the leaders. Then everyone goes back to other work.
Over the next year, the result is often lost. A setting is changed back. A routine stops. The metric is still collected, but nobody reviews it.
Last week's article ended with a question for the end of every project: "Who will look at this number after the project ends?" This article answers it.
The answer is a control plan. Here is what a control plan is, the four lines it needs, how to choose its process owner, an example from a packaging line, a one-page template, and three common problems.
What is a control plan?
A control plan is a short written plan to sustain the gains after a project ends. In DMAIC, the step-by-step method used in Lean Six Sigma, it is the main output of Control, the last phase.
It answers one question: who looks after it now?
During the project, the project team tracks the metric. When the project closes, the team goes to other work. The control plan says who takes over as process owner, which metric they track, and what they do if it changes.
A good control plan is short. It fits on one page. It uses plain words, so a new person can read it and know what to do.
The four lines on one page
Every control plan needs four lines.
The metric. One metric, with an operational definition, so that two people would measure it the same way. Use the definition from the project's data collection plan. If people read or count the metric by hand, check the measurement system before you trust it.
How often it is measured, and where it is posted. Every shift, every day or every week. Pick a frequency that shows a change while it is still small. Post it where the process owner already looks: a board, a report or a meeting.
The process owner, and a backup. One name for the process owner. One name for the backup, who covers when the owner is away.
The reaction plan. The control limits for the metric, and the first two or three things to check if it goes outside them. The control limits are the range the metric normally stays inside. Calculate them from data collected after the improvement, not from the project's baseline, because the process has changed.
Everything else is extra. Some teams add the settings the project changed, or the reason for each change. That helps, as long as the plan still fits on one page.
How to choose the process owner
The process owner is the most important line on the plan. Without a process owner, the plan is usually not read after the first month.
Ask these questions to choose the process owner.
Is it one person? "The quality team" or "Operations" is not a process owner. A team cannot be asked about the metric at the Monday meeting. Name one person.
Do they run the process every day? The best process owner is usually the supervisor of the line, the shift or the office where the work is done. A project lead who sees the metric once a month sees a change too late to act on it.
Can they act on the metric? If the metric moves, the process owner should be able to start the reaction plan without asking for permission.
Have they said yes? Ask them. Show them the plan and agree on it together. A person who is named as process owner without being asked often does not know they are the owner.
Do they have the time? Reviewing one metric takes a few minutes a week. Make sure their manager agrees they have those minutes.
Who is the backup? Name a second person, so the metric is still reviewed when the process owner is away or changes jobs.
An example: the packaging line
A food plant ran a project on one packaging line. The line wraps trays of food in clear plastic film. Too much film was being thrown away: at start-up, after each roll change, and when the film tore.
The team found the causes and fixed them. Less film was thrown away, and the project closed.
The team wrote a control plan. It was 14 pages long. It listed every setting, every cause and every study the team had run. It went into a shared folder. After the first week, nobody opened it.
A few months later, the team cut it to a one-page control plan with four lines:
Metric: film thrown away each shift, as a percent of the film used.
How often, and where: measured every shift, written on the line's board at the end of the shift, and reviewed in the Monday meeting.
Process owner: the packaging line supervisor. Backup: the second-shift lead.
Reaction plan: if the metric goes above its upper control limit, check the film tension setting, check the roll for damage, and ask the operator what was different at start-up.
The 14 pages stayed in the folder for anyone who needed the detail. The one page went on the board next to the line. The supervisor used it every week, and film waste stayed near the level the project reached.
A one-page template
The four lines are the core. This template adds a few short fields around them. Copy it, and fill it in together with the process owner.
Control plan: [name of the process]
The gain: what the project changed, in one sentence.
Metric: its name, its operational definition, and where the data comes from.
Control limits: the range the metric normally stays inside when the process runs as it should.
How often it is measured: every shift, every day or every week.
Where it is posted: the board, the report or the meeting.
Process owner: one name. Backup: one name.
Reaction plan: the first two or three things to check if the metric goes outside its control limits, and who to call.
What the project changed, and why: one line for each change, so nobody undoes it without knowing the reason.
Date agreed: and the date of the first review.
Three common problems
The plan is too long. A long plan is written for the project team, not for the process owner. Keep the detail in the project file. Give the process owner one page.
The process owner is a team or a department. "Owner: Maintenance" names nobody in particular. When the metric moves, each person thinks someone else is reviewing it. Name one person.
The process owner cannot see the metric. The metric is in a report the owner never gets, or it comes once a month. Post the metric where the owner already looks: the line's board, the daily meeting or the shift report.
The reaction plan
The fourth line of the control plan is the reaction plan. It says what the process owner checks first when the metric goes outside its control limits, and who they call.
Write those first steps on the page, in plain words. Then the owner does not have to work them out on a busy day. A later article covers the reaction plan in full.
Before you close the project
If you lead the team, use a few minutes of the Control tollgate review to make sure the gains will be sustained.
Meet the process owner, not only the project lead.
Ask the process owner to explain the control plan in their own words.
Check that the metric is posted where the owner already looks.
Give the owner the time, and say so to their manager.
Agree on the date of the first review, about a month after the project closes.
I write one of these every week, based on what actually happens on projects rather than what the textbook says should happen. You can join the newsletter here.
FAQ
What is a control plan?
A control plan is a short written plan to sustain the gains after a project ends. It names one process owner. It says which metric to track, how often it is measured, where it is posted, and what the reaction plan is if the metric goes outside its control limits.
What should a control plan include?
Four lines: the metric, how often it is measured and where it is posted, the process owner and a backup, and the reaction plan. Many teams also add the control limits, what the project changed and why, and the date of the first review.
Who should own a control plan?
The process owner: one person who runs the process every day and can act on the metric. Often this is the supervisor of the line, the shift or the office. The process owner should agree to the job, have the time for it, and have a named backup.
How long should a control plan be?
One page. Keep the detail in the project file. The process owner needs the four lines, written in plain words.
What is the difference between a control plan and a reaction plan?
The control plan says how the gains are sustained: the metric, how often it is measured, and who the process owner is. The reaction plan is the part that says what to do when the metric goes outside its control limits. A short reaction plan is written on the control plan's page, as its fourth line.
Name one process owner. Write the control plan on one page.
