Overall Equipment Effectiveness (OEE) measures losses during scheduled production. Total Effective Equipment Performance (TEEP) extends a Lean Six Sigma capacity assessment to the full calendar. The denominator changes: OEE uses scheduled production time; TEEP includes time outside that schedule. (dergipark.org.tr)
For practitioners considering Lean Six Sigma International’s Certificeringsprogrammer, choosing between OEE and TEEP is an exercise in defining project scope. The projektkontrakten should identify the decision the measure will support: recovering output within existing shifts or assessing whether the production schedule should change.
OEE measures losses within scheduled production
OEE is the product of availability and performance, multiplied by quality. NIST’s manufacturing-data guidance, published in July 2020, defines availability as uptime and performance as operating speed relative to design. Quality is first-pass yield. Counting repaired output as first-pass success conceals the original quality loss. (nvlpubs.nist.gov)
For a single product with a defined ideal cycle time, research published in January 2021 in Applied Sciences presents the following calculation: (mdpi.com)
- Availability = operating time ÷ scheduled production time.
- ydeevne = (ideal cycle time × total units produced) ÷ operating time.
- Quality = good units ÷ total units produced.
- OEE = availability × performance × quality.
The factors are multiplied as decimal fractions and the result expressed as a percentage. In a DMAIC project, the component measures belong alongside OEE. Downtime records identify stoppages; speed and defect records explain losses that the aggregate score cannot locate. The US Environmental Protection Agency describes this use of OEE to investigate losses within Total Productive Maintenance. (epa.gov)
TEEP extends the denominator to calendar time
TEEP covers the full calendar period, including hours when production is not scheduled. With consistent definitions, TEEP = OEE × loading, where loading is scheduled production time divided by calendar time. The January 2021 Applied Sciences paper describes this relationship between equipment utilisation and OEE. (mdpi.com)
A Lean Six Sigma capacity review needs a separate loading figure. Reporting scheduled hours separately lets the sponsor distinguish a scheduling change from a change in performance during those hours. Neither OEE nor TEEP explains why production was unscheduled.
A published case: higher OEE alongside lower TEEP
A 2022 study by Hatipoğlu and Akar compared equipment measures over 12 months at a Turkish faucet-production facility. Between January and November, OEE increased while TEEP decreased. A Lean Six Sigma sponsor looking only at OEE would miss that decline in calendar-time performance. (dergipark.org.tr)
| Reported month | OEE | TEEP |
|---|---|---|
| January | 89.65% | 63.10% |
| November | 91.20% | 59.92% |
The authors also identified deficiencies in the facility’s loss-classification scheme. (dergipark.org.tr) For a DMAIC team, that finding makes reconciliation of scheduled time with calendar time the next step before proposing additional equipment. The reported percentages alone cannot establish whether unused hours were commercially recoverable.
Select the measure through the project charter
The decision owner and required evidence determine whether an OEE or TEEP project fits the problem:
- Recurring losses during scheduled shifts: OEE and its components provide the starting measures. A Paretodiagram of recorded losses helps the team select an improvement target.
- Additional shifts or equipment investment: TEEP shows calendar-time performance; OEE and loading explain how it was calculated. The Projektsponsor needs documented demand and staffing assumptions before treating unscheduled hours as available capacity.
- Unexplained differences between dashboards: measurement reconciliation is the first project deliverable. Time boundaries and loss codes must agree before the team compares performance.
When breakdowns dominate the loss records, TPM practices warrant investigation. Setup losses call for an assessment of SMED opportunities. The EPA’s TPM guidance distinguishes equipment failures from setup and adjustment losses. An improvement proposal should identify which loss it will address. (epa.gov)
Define the measurement rules before claiming improvement
In the DMAIC Measure phase, the baseline needs a written operational definition. That definition specifies the equipment boundary and reporting period, with a source for the ideal cycle time. It also explains how breaks and changeovers enter the calculation, and how planned maintenance is classified. Without those rules, a reviewer cannot reproduce the OEE percentage.
The good-unit count should follow first-pass yield, consistent with NIST’s 2020 definition. Separate rework records let the team investigate the original defect and the effort spent correcting it. (nvlpubs.nist.gov)
Changes to scheduling rules belong in the Styringsplanen. Whenever production time is reclassified, a reconciled before-and-after calculation lets the sponsor trace the claimed OEE gain to operating records and assess how much came from the classification change.
Lean Six Sigma Internationals Certificeringsprogrammer cover DMAIC problem solving. Green Belt training includes MSA and statistical process control, subjects relevant to practitioners responsible for validating OEE inputs and analysing process variation. (leansixsigma.org)
Kilder
- NIST (2020), Recommendations for Collecting, Curating, and Re-Using Manufacturing Data: https://nvlpubs.nist.gov/nistpubs/ams/NIST.AMS.300-11.pdf
- Verimlilik Dergisi (2022), A New Scoring Approach to Calculate Overall Equipment Efficiency: A Case Study: https://dergipark.org.tr/en/download/article-file/2182315
- US Environmental Protection Agency (updated 2026), Lean Thinking and Methods: TPM: https://www.epa.gov/sustainability/lean-thinking-and-methods-tpm
