Process Capability (Cp / Cpk)

Control limits tell you if a process is stable. Capability tells you if it's good enough for your specification.

You enter your spec limits (LSL = lowest acceptable, USL = highest acceptable). SenSight then computes:
  • Cp — how well the spec width fits the process spread (ignores centering)
  • Cpk — the same, but penalizes a process that drifts off-center
Rule of thumb: Cpk ≥ 1.33 = capable (comfortably inside spec); 1.0–1.33 = marginal; below 1.0 = not capable (you're making out-of-spec parts). Cpk is the number quality auditors ask for.
Try it in the app
Try: In the SPC tab, type your LSL and USL values above the chart. The Cp/Cpk cards appear instantly. Watch how Cpk drops if the mean is far from the spec center even when Cp looks fine.
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Run this on your own data

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SPC — Control Charts (Is the Process Stable?)

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t-Test (Are Two Groups Really Different?)