Flowchart
Is this metric change real? A control chart decision
The decision rule to agree before the number moves
A decision flowchart for reading a process behaviour chart on a research metric such as NPS, satisfaction or completion rate. It asks whether a point sits outside the three-sigma limits, whether there is a long run on one side of the centre line and whether there is a steady trend. Any yes is a special cause worth investigating. Three noes mean common cause variation, and the right move is to leave the metric alone.
Where this appears
What's in this flowchart
Start: A research metric moved
- Is a point outside the three-sigma limits?
- No: go to 2.
- Yes: Investigate the special cause. Something specific happened. Find it.
- Is there a long run on one side of the centre line?
- No: go to 3.
- Yes: Investigate the shift. The process level has moved.
- Is there a steady trend across many points?
- No: go to 4.
- Yes: Investigate the drift. Something is changing continuously.
- Finish: Leave the metric alone. It is common cause. To change the level, change the process.
Use this image
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<a href="https://www.koji.so/visuals/is-this-metric-change-real-control-chart-flowchart"><img src="https://www.koji.so/visuals/is-this-metric-change-real-control-chart-flowchart/is-this-metric-change-real-control-chart-flowchart.png" alt="Flowchart for a metric that moved: three questions about limits, runs and trends, each leading to an investigation, ending in leaving the metric alone." width="1200" height="1119" /></a>
<p>Source: <a href="https://www.koji.so/visuals/is-this-metric-change-real-control-chart-flowchart">Is this metric change real? A control chart decision</a>, Koji</p>
