Run Chart

Img Print a Handout: Run Chart (PDF)

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: QI Toolbox: Control Chart

How to Create a Run Chart

  1. Choose which data you will measure and track
  2. Gather data: Generally, collect 20-25 data points, with which you can detect meaningful patterns over time
  3. Create a graph on which you can plot your data (y axis, or vertical line) over time (x axis, or horizontal line)
  4. Plot the data
  5. 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").

Test #3: The presence of a trend

A trend is defined as an unusually long series of consecutive increases or decreases in the data, (usually at least 6 or 7).

Example: Isanti County, WIC No-Show Rate

This run chart from Isanti County shows the percentage of WIC appointments missed over a 1.5-year period.

Click to view larger image.

Run Chart

More Examples of Run Charts

Further Reading