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Statistical process control

Statistical process control (SPC) helps you see whether an operational measurement remains stable over time. A Chipper control can chart event counts or proportions, individual values, average values, or variability. It uses one or more rules as its source and analyzes the resulting series within the method or instrument scope you choose.

Create a control​

Go to Monitor → SPC and select:

  • New control to choose the measurement and scope yourself.
  • Set up with AI to review suggested controls before creating them.

During setup, choose the instrument type, measurement rule, scope, series grouping, and chart type. Chipper supports views scoped by method, instrument, their combination, or an aggregate where the data permits it.

Review the chart before alerting​

A new control is created with alerting off so you can inspect the data first. Check:

  • Whether the measurement and unit are correct.
  • Whether the chosen methods or instruments should share a baseline.
  • The baseline period used to calculate limits.
  • Fixed or rolling limit behavior.
  • The rolling-average window.
  • Points outside the control limits and any selected Nelson-rule patterns.

The chart's display range and its baseline window are separate. Changing the visible date range should not silently redefine the baseline used to calculate limits.

Turn monitoring on​

When the chart represents a useful operating baseline:

  1. Turn Alerting on.
  2. Select Edit what raises an alert.
  3. Choose the limit or Nelson-rule patterns that should fire.
  4. Configure severity and notification destinations.
  5. Save the changes.

SPC alerts appear in the same Alerts workflow as deterministic rule alerts, with a link back to the control that fired.

Use the SPC dashboard to group controls by method or instrument and focus on the controls that need attention. Switch to the table for full filtering and configuration status.