Summary of the six-sigma MEASURE stage

The purpose of the Measure phase is to fully understand the current performance by identifying how to best measure current performance and to start measuring it. The measurements used should be useful and relevant to identifying and measuring the source of variation. This phase includes:

• identify the specific performance requirements of relevant Critical-to-Quality (CTQ) characteristics;
• map relevant processes with identified Inputs and Outputs so that at each process step, the relevant Outputs and all the potential Inputs (X) that might impact each Output are connected to each other;
• generate list of potential measurements
• analyze measurement system capability and establish process capability baseline;
• identify where errors in measurements can occur;
• start measuring the inputs, processes and outputs and collecting the data;
• validate that the problem exists based on the measurements;
• refine the problem or objective (from the Analysis phase)

Key questions:

• What is the Process? How does it function?
• Which Outputs affect CTQ’s most?
• Which Inputs affect Outputs (CTQ’s) most?
• Is our ability to measure/detect sufficient?
• How is our current process performing?
• What is the best that the process was designed to do?

The most applicable tools at this phase include the following:

• Fishbone Diagram – to demonstrate the relationships between inputs and outputs
• Process Mapping - to understand the current processes and enable the team to define the hidden causes of waste.
• Cause & Effect Matrix - to quantify how significant each input is for causing variation of outputs.
• Preliminary Failure Mode & Effect Analysis (FMEA) - using this in the Measure phase helps to identify and implement obvious fixes in order to reduce defects and save costs as soon as possible.
• Gauge Repeatability & Reproducibility (GR&R) - used to analyze the variation of components of measurement systems so minimize any variation in the measurement systems.