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Measure · Tool guide 22 of 40

Run Chart

A run chart plots a measure in time or observation order, often with a median reference line. It makes trends, shifts and unusual sequences visible. It has no statistically estimated control limits unless it is converted into a control chart.

Expected output: A time-ordered plot with contextual annotations and cautious pattern interpretation.

01 · Purpose

Why and when to use it

Use it as an initial view of process behaviour over time and to place changes in context.

Who takes part?

The measurement owner works with people who understand the process and the recorded data. Statistical or measurement-system decisions should involve someone able to check the assumptions and study design.

02 · Application

How to apply it

Start with an agreed measurement purpose, explicit units and trustworthy observations. Identify missing cases and assumptions before calculating.

  1. Retain the true observation order and consistent measurement intervals.
  2. Plot values with units and time labels.
  3. Add a baseline median where useful.
  4. Annotate known process or measurement changes.
  5. If applying run rules, state a recognised rule set and its handling of ties; investigate signals.

03 · Example

A worked measurement example

Original fictional teaching example. Small datasets illustrate the method; they are not proposed as sufficient study sizes. Supplied parameters are assumptions, not estimates from a real process.

DayPacking time (minutes)
1, 2, 3, 4, 54, 5, 4, 6, 5
6, 7, 8, 9, 108, 9, 8, 10, 9
Day 1Day 10Minutes0510
Packing durations by day; later observations are higher.

04 · Interpretation

What the result tells you

The later observations are higher than the earlier ones. This prompts investigation of changes around day six; ten fictional observations alone do not verify a cause.

Completion check: A time-ordered plot with contextual annotations and cautious pattern interpretation.

05 · Judgement

Mistakes and limitations

Do not sort values by size before plotting. Sampling frequency and autocorrelation affect interpretation. A median is neither a target nor a control limit.

07 · Reading

Sources and further reading

The tool list follows the accepted LeanTrainingLab overview and its reference to Six Sigma+Lean Toolset, second edition (Lunau, editor; Springer, 2013). The book chapters were not available for direct review during this build. Explanations, examples and worksheets are original teaching material. Further reading supplies professional background; local conventions are stated explicitly.