Glossary
This is the single source of truth for all acronyms used across the Time Hierarchy page and this reference. All terms are listed alphabetically.
| Abbreviation | Full Name | Definition |
|---|---|---|
| BNS | Bottleneck Speed | Maximum demonstrated sustainable speed of the constraining process step |
| LTMW | Lost Time Making Waste | Time equivalent of producing defective output. Formula: Waste Output / Run Speed |
| LTSR | Lost Time Slow Running | Time equivalent of running below BNS. Formula: Good Output / Run Speed − Good Output / BNS |
| OEE | Overall Equipment Effectiveness | PT / PPT. Measures execution within planned production time. Equivalent to Good Output / (PPT × BNS). Note: industry-standard A × P × Q is the multiplicative form; majaco uses the additive equivalent |
| OOE | Overall Operations Effectiveness | PT / Shift Time. Management metric covering all shift losses including schedule loss and PDT. Same formula as “Machine Efficiency” — name signals production context |
| PDT | Planned Downtime | Scheduled stops: changeovers, planned maintenance, start-of-shift checks |
| PPT | Planned Production Time | Shift Time − Schedule Loss. Time explicitly scheduled for production |
| PT | Potential Time | Good Output / BNS. Theoretical minimum time to produce actual good output at maximum bottleneck speed |
| TEEP | Total Effective Equipment Performance | PT / Calendar Time. Strategic metric for production-constrained environments |
| UMP | Unit Marginal Profit | Revenue minus truly variable costs per unit |
| UPDT | Unplanned Downtime | Breakdowns, stoppages, material/labour waiting |
Time Hierarchy
Every level is formed by subtracting a loss category from the level above. The result is PT — the theoretical minimum time to produce your actual good output at BNS.
For the full interactive hierarchy with expandable levels, see the Time Hierarchy page.
Core Formulas
Efficiency Metrics
| Metric | Formula | Denominator scope | Audience | Constraint context |
|---|---|---|---|---|
| Operating Efficiency | PT / Operating Time | Losses within operating time (UPDT, LTSR, LTMW) | Shop floor | Both |
| OEE | PT / PPT | Adds PDT | Operations | Both |
| OOE (Machine Efficiency) | PT / Shift Time | Adds Schedule Loss | Management | Both |
| TEEP | PT / Calendar Time | Adds Non-working Time | Strategic | Production-constrained |
| Output per Labour Hour | Good Output / Labour Hours | N/A | Strategic | Sales-constrained |
Equivalence proof
Since PT = Good Output / BNS:
Every metric in the table follows this pattern: good output as a proportion of what could have been produced in the denominator time window at BNS.
Widening denominator logic: each metric widens the denominator one level up the hierarchy. Operating Efficiency measures execution; OEE adds PDT accountability; OOE adds schedule loss; TEEP adds non-working time. Choose based on who is accountable for the losses in scope.
Machine Efficiency vs OOE: Machine Efficiency and OOE are the same formula (PT / Shift Time) — the name changes with strategic intent. Use “Machine Efficiency” in a sales-constrained context; “OOE” in a production-constrained context.
For financial valuation of lost time (production-constrained vs sales-constrained), see the Time Hierarchy page.
Diagnostic Quick Reference
LTSR Elevated?
Two possible causes — the fix is different for each:
- True slow running — the line deliberately operates below BNS (e.g. operator reduces speed for quality reasons).
- Micro-stops — the line runs at full speed between frequent brief stops that are too short to log as UPDT but reduce the average Run Speed.
Diagnose with a lineside time study: observe whether the line speed setting matches BNS, or whether frequent micro-stops are dragging the average down.
UPDT Prioritisation
Use a frequency–duration matrix to prioritise UPDT events:
| Low Duration | High Duration | |
|---|---|---|
| High Frequency | Highest value — often missed; frequent short stops that aggregate to large losses | Major chronic issue — visible and usually already being addressed |
| Low Frequency | Noise — low total impact | Rare catastrophic events — address through preventive maintenance |
MECE Verification
Operating Time (Actual) must equal PT + LTSR + LTMW + UPDT. If it does not balance, a loss category has been mis-allocated. Check Run Speed and BNS inputs first.
See what your lost time is costing you
majaco can implement this framework in your facility — from data collection design through to live dashboards and financial valuation.
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