Run Chart - MN Dept. of Health (2024)

What is a run chart?
How to create a run chart
Using a run chart to test for special causes
Examples of run charts
Further reading
Sources

What is a run chart?

A run chart is used to study collected data for trends or patterns over a specific period of time. A run chart will help you:

Monitor data over time to detect trends, shifts, or cycles
Compare a measure before and after the implementation of solution to measure impact
Focus attention on vital changes, not normal variation
Track useful information for predicting trends

The run chart is a running record of a process over time:

The vertical axis represents the process being measured
The horizontal axis represents the units of time by which the measurements are made
The centerline of the chart is the mean or average

A run is defined as one or more consecutive data points on the same side of the mean line.

See Also: PH&QI Toolbox: Control Chart

How to create a run chart

Choose which data you will measure and track
Gather data: Generally, collect 20-25 data points, with which you can detect meaningful patterns over time
Create a graph on which you can plot your data (y axis, or vertical line) over time (x axis, or horizontal line)
Plot the data
Interpret the chart: Focus on the vital changes or meaningful trends/patterns, rather than each and every data variation; keep reading for interpretation tips

Using a run chart to test for special causes

Test #1: The presence of too much or too little variability

Use when there are too few or too many runs.

Test #2: The presence of a shift in the process

A special cause exists if a run contains too many data points (i.e., with 20 or more data points, a run of 8 or more data points is considered "too long"; with less than 20 data points, a run of 7 might also be considered "too long").