Statistical Process Control (SPC) Resource Center

Special Control Charts for Special Applications

There are variations on the standard X-bar & R Charts which may be more appropriate in certain manufacturing situations.

Variations on the R Chart include:

  • R – Monitors range within a subgroup.
  • MR – Monitors range between subgroups.
  • RD – Monitors range of parameter difference.
  • s – Monitors the process standard deviation.

Variation on the Chart include:

  • X-Bar – Monitors the process location with subgroups.
  • IX – Monitors single samples, not subgroups.
  • X-Bard – Monitors the difference between the subgroup average and the historical process average or the nominal of the specification.
  • IXd – Monitors the difference between the individual value and the historical process average or the nominal of the specification.