Last Updated on 13 September 2023
Data from a snapshot in time often doesn’t give you enough information. Run charts (also known as time series plot, trend chart or line graph) show the change in a variable over a period of time. This can show you if variations are natural over time, whether there’s any seasonality and if there’s any data trends that give extra information.
Benefits of using a run chart
There are many advantages to using run charts, such as:
- Identify and allow for seasonality, such as low customer contact over summer holidays
- Identify time-dependent patterns, such as high levels of defects at the start and end of the day.
- Show how variables are changing over time, e.g. the trend in defects during a process improvement project will help show if any progress is being made.
Creating a run chart
It is simple to make a run chart:
- Collect your observations over a period of time at regular intervals
- Create a chart with the x axis is time (time goes up from left to right), and the variable data is the y axis.
You will now have your run chart, which will help you identify trends and patterns.
It’s easiest to see how it works from viewing an example, such as this plot of monthly customer complaints:
In this example, customer complaints are mapped in a run chart, with the data put into monthly buckets. It’s obvious from this that customer complaints are reducing over time. This would be harder to see just from the raw data, especially as complaints increased in two of the last three months.