Overall Equipment Effectiveness OEE
A single 0-100% score for how much good product a machine made versus the most it could have made in the time it was scheduled to run.
The fork, why two teams get different numbers
OEE = Availability × Performance × Quality is near-universal; the fork is what
goes into the Availability denominator, "planned production time." Some teams
exclude only breakdowns and setups; others also carve out breaks, planned
maintenance, and no-demand time, each choice moves OEE by double digits on the
same shift. The deeper fork is OEE vs TEEP: OEE measures against SCHEDULED time,
TEEP against ALL calendar time (24×7). A plant running one shift can post a
brilliant OEE and a dismal TEEP simultaneously, both true. Maintenance quotes
OEE (equipment while it was asked to run); finance and capex justification want
TEEP (the asset around the clock).
The trap
Multiplying three ratios makes a soft number look precise: an "85% OEE" can be 98%×98%×88% (a quality problem) or 88%×99%×97% (an uptime problem), the composite hides which.
- The full trap, worked on a real export
- Every formula variant, spelled out
- The reconciliation anchor, what to tie it to and when to refuse
Reference: TPM/OEE convention (Nakajima "Six Big Losses") · APICS/ASCM terminology