Control Charts

Control Charts: are used for determining stability of a process. Important
terms are:

USL - Upper Specification Limit
LSL - Lower Specification Limit
UCL - Upper Control Limit
LCL - Lower Control Limit

First two are set by customer and last two are normally (+-) 3 Sigma.
Normally used to track repititive activities, sometimes they are also used
to monitor

cost and schedule variances, volume and frequency of scope changes.

A process is out of control when seven consecutive data points are above or
below the mean.

-Ishikawa – Cause and Effect diagrams

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