Run Chart

Print a Handout: Run Chart (PDF: 245KB / 2 pages)

Run ChartA 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 center line 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: Control Chart


How to Create a Run Chart

Creating a Run Chart

  1. Decide 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: Testing for Special Causes

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

  • 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).

Examples: Run Charts

Icon

Isanti County: WIC No-Show Rate

In this chart, there are eight runs.

Run Chart
Click to View Larger: WIC No-Show Rate, Isanti County


More Examples of Run Charts

Icon Woodall: The Use of Control Charts in Health-Care and Public-Health Surveillance (PDF: 316KB / 16 pages)
Icon Mohammed, Worthington, and Woodall: Plotting Basic Control Charts: Tutorial Notes for Healthcare Practitioners (PDF: 663KB / 9 pages)

More Information on Run Charts

Further Reading

Icon McCoy and Riley: Basics of the Control Chart (PDF: 220KB / 8 pages)
Icon American Society for Quality: Control Chart
Icon Hanslik, Boelle, and Flahault: The Control Chart: An Epidemiological Tool for Public Health Monitoring
Icon McCoy: Finding the Right Tool for your Purpose (PDF: 466KB / 40 pages)

Source

Icon McCoy and Riley: Basics of the Control Chart (PDF: 220KB / 8 pages)
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