A driver diagram helps you plan an improvement project by showing how your aim connects to the changes you will test. Use it as a living document and update it as your team learns what works.
A driver diagram makes the logic of your project visible. It links the project goal to the high-level factors that influence it, the specific interventions that support those factors, and the practical changes you will test.
What a driver diagram contains
A driver diagram organises your project into connected columns. Each column builds on the one before.
Aim statement
The aim statement sets out the goal of your project. It answers the first question of the Model for Improvement: what are you trying to accomplish?
Your aim should reflect the problem you are trying to address.
Primary drivers
Primary drivers are the high-level factors you need to influence to reach your aim. They are the improvement areas that must be addressed to achieve your desired outcome.
Write primary drivers as clear statements rather than numeric targets.
Secondary drivers
Each secondary driver should:
- contribute to at least one primary driver
- have an evidence base for its likely impact on the outcome
- be necessary and, together with the others, sufficient to achieve the aim.
Brainstorming the causes of the problem is a useful way to identify your secondary drivers.
Change ideas
Change ideas are the specific actions you will take to address each secondary driver. They answer the third question of the Model for Improvement: what changes can you make that will result in improvement?
Each change idea should connect to at least one secondary driver.
Prioritising change ideas
You will not test every change idea at once. For each one, weigh its likely impact on your aim against how easy it will be to put into practice.
Use this to decide which change ideas to test first through a Plan-Do-Study-Act (PDSA) cycle.
Environmental impact
When prioritising change ideas, also consider their positive and negative environmental impacts. You may decide to deprioritise changes that significantly increase environmental harm.
You can measure environmental impact by comparing the resources used before and after a change.
More about sustainability in quality improvement
Measuring improvement
A driver diagram helps you decide what to measure. Outcome, process and balancing measures answer the second question of the Model for Improvement: how will you know if a chance is an improvement?
When setting measures, decide:
- how much improvement do you want to see
- by when.
How a driver diagram supports your project
Once your driver diagram is complete, your team can use it to:
- stay focused on the aim
- explain your project's purpose to others
- show how each activity connects to the outcome
- decide what to measure and monitor
- build support and commitment for the changes you propose.
Update your driver diagram regularly as your team learns more.
Download our driver diagram starter kit (PDF 2.9 MB) to help you draft your first driver diagram.
Video resources: An introduction to improvement science
A six-part video series on improvement science, including driver diagrams. All videos open on YouTube.
- Improvement science part 1
- Improvement science part 2
- Improvement science part 3
- Improvement science part 4
- Improvement science part 5
- Improvement science part 6