2. Measure

This is the second phase in the DMAIC phases of Six Sigma. A measurement system is created, which helps in knowing Ys and identifying potential Xs for the Six Sigma initiative. A measurement system is established to ensure that the data collected for the six sigma project is accurate.

In Define Phase – the phase prior to Measure, the potential projects (problems/opportunities (Ys)) are identified. Approximations of the size of the six sigma project are taken to draft a schedule. In the Measure phase, the actual indicators are identified and the quantum of work is identified. This gives the correct estimate of the volume of work on hand, which helps in accurate estimations.

The data collected for the six sigma green belt project should have the following characteristics:

• Accurate (Observed value should be equal to the actual value), no matter how many times the task is performed.
• Repeatable (When a person performs the task twice, he should be able to yield the same results)
• Reproducible: (When two persons measure the same item, the results should be identical.). An example of reproducibility is software estimates. No matter who does it, the estimates should be in close proximity to one another (i.e. they should not vary much).
• Stable: The results should be stable over a period of time.

The roadmap for "Measuring" is as shown in the diagram above.

Note: that the first three steps could have been done in the Define phase itself. In the define phase, an approximate of Y’s volume is taken, while in the Measure phase, the actual volume of Y is calculated. If in the Define phase, only the approximate idea of size of Y is known, then the first three steps are required in Measure phase, otherwise not. On the other hand if you know the size in the Define phase itself, then the first three steps in the Measure phase can be avoided.

To summarize, we carry out the following under the Measure phase:

1. To select the appropriate Y, we use the following:

a. Sigma Level (Performance of Y)
b. RTY (Rolled Throughput Yield)
c. CP(Inherent process capability), and CpK (Resultant process capability)

2. Identify the Xs and prioritize, we use the following:

a. Process mapping
b. Fish bone diagrams
c. Pareto analysis
d. FDM (Function Deployment Method)

At the end of step 2, we have the list of prioritized Xs.