367. Cheatsheet

Index Formula Variation
Used
Assumes
Process
Centering
Measures
Short-term
()
Yes Pure “noise” under stable conditions (same machine, same operator, same material, no maintenance events)
Short-term
()
No Pure “noise” under stable conditions (same machine, same operator, same material, no maintenance events)
Long-term
()
Yes Real-life variability from all causes (data across multiple shifts, operators, material batches, maintenance)
Long-term
()
No Real-life variability from all causes (data across multiple shifts, operators, material batches, maintenance)
  • Short-term
    ()
  • Deviation
    from target
    ()
No Penalizes deviation from target (); reflects capability under stable conditions when target matters

Centered v. Decentered Process