Tag Archives: run chart

All About Run Charts

Run Charts are simple line graphs of data plotted over time. They are used to better-understand the performance of a process, as they help people distinguish between random variation and special causes, or to track information and predict trends or patterns.

A run chart can also reveal whether a process is stable by looking for a consistent central tendency, variation and randomness of pattern.

One of the most common CI tools, a run chart is easy to interpret and does not require tedious calculations or special software to produce.

Sample Run Chart

How to create a run chart:

    1. Identify the question that the run chart will answer and obtain data that will answer the question over a specified period of time. For example, if you were looking at how long it takes to complete a task, you will make note of the time taken (in minutes) to complete it over a specified period of time.
    2. Gather data, generally collect at least 10 data points to detect meaningful patterns.
    3. Create a graph with vertical line (y axis) and a horizontal line (x axis).
    4. On the vertical line (y axis), draw the scale related to the variable you are measuring. In our example, this would include the complete range of observations measuring time-to-completion
    5. On the horizontal line (x axis), draw the time or sequence scale.
    6. Plot the data, calculate the median and include into the graph.
    7. Interpret the chart. Four simple rules can be used to distinguish between random and non-random variations:
      1. Shift – 6 consecutive points above or below the median
      2. Trend – 5+ consecutive points going up or down
      3. Too many/too few runs – too few or too many crossings of the median line
      4. Astronomical data point – a data point that is clearly different from all others (often a judgement call)

Continuous Improvement & Key Charting Tools

In an earlier post we shared thoughts on “Ten Continuous Improvement Tools,” each of which designed to help people  examine current reality from a different angle.

Included in the list are several key charting tools, which are particularly useful for sifting through potentially large quantities of data and translating the data into more useful information. These tools also make the work more “visible,” and give those involved in studying the work a common language.

Here is a list of five key charting tools:

  1. paretoPareto: simple bar chart that ranks and displays data in descending order, and that helps us decide what to work on — the “vital few” vs. the “less important many.”  Often referenced as the 80/20 principle.
  2. runchartRun:  A run chart is a graph that displays data points of some characteristic being measured as they occur over time. It is used to visually display process performance over time and to identify meaningful trends or shifts in the average, thus telling us  “how things are going” and prompting us on what to investigate further.
  3. flowchartFlow: A flow chart is a simple diagram of the steps in a process. It is used to identify actual or ideal paths that a process follows, and shows basic steps and decision points, recycle loops, work and wait times, and can highlight problems or opportunities for improvement
  4. histogramHistogram: A column chart showing the distribution of values by frequency. It is a set of data with a range of measurements. The height of a bar corresponds to the relative frequency of the amount of data in the class.
  5. fishboneFishbone: A charting technique used for identifying all of the possible causes of particular “effect” or problem… for linking conditions for results. A fishbone chart can help us identify root causes of problems by asking the simple question,  “why?”  multiple times.