Reading control charts
Use control charts to tell normal variation from real change: centre lines, control limits versus specification limits, common out-of-control signals, and how to react without over-adjusting.
- Level
- Intermediate
- Length
- About 50 minutes
- Contents
- 3 lessons · 1 video · final exam
- Status
- Published · updated 1 Oct 2026
Skills you'll practise
- Explain the difference between control limits and specification limits
- Distinguish common-cause from special-cause variation on a chart
- Recognize common out-of-control signals using a stated rule set
- Choose the right reaction to a signal, and avoid adjusting a stable process
Course outline
- 1.Reading control chartsVideo · 2 min
- 2.Variation and what a control chart showsLesson · 16 min
- 3.Control limits, specification limits and signalsLesson · 18 min
- 4.Reacting to signals without over-adjustingLesson · 16 min
- 5.Reading control charts: knowledge checkKnowledge check · 20 questions
- 6.Seven above the lineScenario
- 7.Final exam7 questions · passing it completes the course, so people who already know the material can test out
Sources it draws on
The lessons and questions are written from these references, so learners can go back to the original.
- General statistical process control (SPC) practice; Shewhart control charts
- Your site's control plan, chart rules and reaction plans
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