Understanding Variation: Part1- the Run Chart

Abstract

This paper briefly describes different types of data, how to collect data, the rationale for organizing data in a time-ordered fashion, and how to use a simple tool called a run chart to present and analyze data. The run chart is simple to construct and equally as simple to analyze. Run charts make variation visible and determine whether a change has made an improvement and if the improvement is being sustained. Two probability rules accompany run charts to help answer the question "How will we know that a change is an improvement?". These rules provide an objective statistical threshold to determine whether changes from quality improvement efforts are having an impact. Quality improvement and data go hand-in-hand. To qualify as quality improvement, projects should have a well-developed data collection and analysis strategy. A run chart and the rules presented in the following paper are simple, statistically valid tools used to answer the question "How will we know that a change is an improvement?".