The Capability Analysis (Poisson) report measures the stability of a single process step (or data-collection point) over time and reports on the long-term capability (using DPU, there is no DPMO or Z) of that step based on the observed average defective rate. You can use this report for projects in which the measurement system is only capable of counting the number of defects observed in a unit as a means of measuring performance.
|When to Use||Purpose|
|Start of project||Perform a baseline capability analysis on the process to determine the capability of a single process step, or data-collection point, at the start of the project. A baseline analysis helps you set improvement goals for the project.|
|Mid-project||Perform a confirmation capability analysis after improvements have been implemented to confirm that the process performs as predicted.|
|End of project||Perform a capability analysis after implementing controls to obtain a final assessment of process capability, and also to determine whether the improvement goals of the project were attained.|
Discrete numeric Y (number of defects), size of inspected unit (for example, square inches of surface or words of text).