December 2026 CPHQ Prep Virtual Class-CPHQ Virtual Live Review Course

CPHQ Virtual Live Review Course | Video: Run Charts

Video Transcription

Video Summary

A run chart is a line graph of data plotted in chronological order over time to show variation and detect meaningful change, though it cannot determine process stability (only a control chart can). The x-axis shows the sequence/time and the y-axis the measured value; points may be connected when time-based. Process changes should be annotated. If changes aren’t visually obvious, add a median (center line) and apply four probability-based rules to identify statistically significant change: (1) Shift—6+ consecutive points above/below the median (skip points on the median). (2) Trend—5 consecutive points all increasing or decreasing (ignore duplicates). (3) Runs—too many/few runs vs a table. (4) Astronomical—an obvious outlier.

Keywords

run chart

time series

process variation

median center line

statistical change detection