── ── Mental model
Theory of Constraints
Theory of Constraints (TOC) — Eliyahu Goldratt, 1984: throughput of any multi-step system is determined by its single bottleneck. Improving any other step produces no system-level gain. The Five Focusing Steps (Identify → Exploit → Subordinate → Elevate → Repeat) are the operational discipline.
How it works
Step 1 — Identify: map all steps with capacity; find where WIP accumulates — that's the constraint. Step 2 — Exploit: max output from the constraint with no new investment (eliminate idle time, defects, distractions at that step). Step 3 — Subordinate: pace all other steps to the constraint's rate. Upstream: don't over-produce. Downstream: don't block. Retire local efficiency metrics that incentivize over-production. Step 4 — Elevate: if still binding after Steps 2-3, add capacity at the constraint (equipment, people, redesign). Highest ROI investment in the system. Step 5 — Repeat: bottleneck has moved. Return to Step 1.
When to use it
- user says 'everyone is working hard but results are flat', 'where is our bottleneck', 'we keep adding capacity but throughput doesn't improve', 'backlog piling up at one stage', 'Goldratt / TOC / Five Focusing Steps', or is designing a process-improvement initiative and wants to know where to invest
When not to use it
When the decision is routine and reversible, applying a formal method costs more than it returns.
Worked example
Goldratt's The Goal (1984) and TOC's Lineage
The Theory of Constraints was developed by Eliyahu Goldratt (1947-2011), an Israeli physicist who applied physics-style systems thinking to management. Goldratt was educated in physics at Bar-Ilan University and Tel Aviv University; his early career was in scheduling software. In the late 1970s, Goldratt developed an approach to plant scheduling that explicitly identified bottlenecks and scheduled the entire plant around them — the operational core of what became TOC.
Install this skill (free, MIT)
npx skills add deciqAI/knowledge-skills