Improvement Cymru Academy - Toolkit Guide - Run Charts - What is a Run Chart - How to Create a Run Chart

Oct 13, 2026

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Improvement Cymru Academy Toolkit Guide explains how run charts visualize data over time to assess whether change tests produce improvement. It covers the purpose of comparing performance measures before and after change, making process performance visible to stakeholders, and monitoring variation. The guide details how to design axes, plot data points, add and freeze the median after sufficient points, annotate tests using PDSA, and interpret common-cause versus special-cause variation using S.T.A.R. rules like shift and trend.

LanguageEnglish

CategoryPresentations

FormatPDF

Pages21

Reading Time7 min

AccessFree to download

What is a Run Chart?

Rationale

When to use a Run Chart?

How to create a Run Chart?

Key chart components (x-axis, y-axis, centre line/median)

Step-by-step creation process

Interpreting a Run Chart

Random variation (common cause)

Non-random variation (special cause)

Identifying improvement: S.T.A.R. rules (Shift, Trend, Astronomical point, Runs)

Improvement Cymru Academy Toolkit Guide Run Charts What is a Run Chart? Run Charts are graphs of data over time. It allows us to see whether the tests of changes we have introduced have had the desired effect and resulted in an improvement. Run charts are one of the most useful tools in improvement. Rationale Run Charts allow a comparison of a performance measure before and after tests of change are conducted. Which help us to see if our changes have resulted in an improvement. They make process performance visible to all stakeholders. When to use a Run Chart? A Run Chart helps teams to understand how a process is performing. They also help to understand variation in the system, which is key in making improvements in processes and systems. It enables you to monitor the performance of one or more processes over time and allow identification of signals of improvement. How to create a Run Chart? There are characteristic of a run chart to be aware of: • On the horizontal (x-axis) data is displayed in chronological order, example Jan Feb March or 1, 2, 3. • On the vertical (y-axis) is the measure of interest, for example a count, a rate or a percentage. • Data points are plotted on the graph and a centre line (CL) is added between the data points. The CL is called the Median. Median: is the number in the middle of the dataset when the data are placed in sequential (ascending or descending) order. If the number of observations is even, the median is the average of the two middle values. The median isn’t significantly influenced by extreme values in the data compared to other averages, such as mean. (Improvement Cymru Academy Toolkit Guide Measures of central location for further information using the median). Diagram 1 | Measuremnt of Characteristic | 20
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A typical run chart

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Number of weeks | | --- | --- | --- | | Measurement of Characteristic Median | | | Example: How to create a Run Chart? 1. Add a useful title that describes your data e.g. Number of people on the waiting list Plan data collection and start to obtain. 2. Design the horizontal axis (x) Place a time scale, with appropriate intervals. Cover period of interest, not just currently available data. 3. Design the vertical axis (y) Add the measure scale, make sure there are appropriate intervals. Most of the data will lie in the middle-half of the chart (shaded here) . Leave enough space for future changes. Use whole numbers. 4. Label the chart Label your axis Explain the x and y axis. 5. Plot data As soon as you have the data plot individual points. Connect the points by a line, from point to point in time order. 6. Plot the median This is the middle value: half the data points above and half below. After 10 points (we recommend you then freeze the median line and extend if no apparent changes) . This helps any changes in the new data to stand out. The line changes from a dashed line to a solid line. Can be a good indicator with fewer points ( but don’t use the probability-based tests and but this will affect the accuracy of your analysis) . 7. Add more information. PDSA 1 Label the unusual events. Mark on the place where the changes were tested (e.g. PDSA 1) or any further important information. This is known as annotation. Interpreting a Run Chart: Variation is part of everyday life and every process has variation. However it is easy to intervene in the process to a single or mostrecent point. Your approach must depend on which type of variation is present. Random Variation (Common cause) : It is stable and a consistent pattern of variation, common cause or ‘chance’. Typically, this type of variation occurs as a result of day-to-day variation in the process. For example, the time it takes to drive to work, the number of steps you do in a day. Res

FAQs

What is the purpose of using a run chart?

A run chart displays data over time so teams can see whether tests of change had the desired effect and led to improvement. It also helps make process performance visible and supports monitoring of performance across one or more processes.

How do you set up the axes in a run chart?

Use the horizontal (x) axis for chronological order with an appropriate time scale, and the vertical (y) axis for the measure of interest such as a count, rate, or percentage. Ensure the y-axis uses an appropriate measure scale with suitable intervals.

When should you plot the median and what is the role of freezing it?

Add the median as the centre line after plotting data points. After 10 points (recommended), freeze the median line and extend it for new data so any later changes stand out clearly.

Oct 13, 2026

Upload by Finn