Picture your projects as water flowing through a riverbed. Wherever an obstacle sits, work piles up behind it: lead times grow, due dates collapse, and everyone multitasks harder — which piles the work up higher.
Goldratt's Rules of Flow remove those obstacles one by one, and Critical Chain keeps the stream protected. The result: projects that finish.
Project organisations don't underperform for lack of effort. They are trapped in self-reinforcing loops — each one feels like diligence from the inside, and each one feeds the next.
Workload exceeds capacity → the backlog grows → urgencies multiply and priorities keep shifting → everyone multitasks → every task takes longer → the backlog grows further.
Selection criteria are too vague to say "no" → low-impact projects multiply → resources spread thin → high-value projects are compromised → underperformance triggers even more "fix" projects.
Work starts without complete inputs → critical pieces are missing → delays and rework stretch the timeline → experts firefight instead of preparing → the next start is even less ready.
Everyone picks their next task on local convenience → priorities drift from project completion → problems surface late, at integration → pressure to "start ASAP" grows → local priorities take over even more.
High uncertainty plus deadline pressure → "there's no time for buffers" → everything starts and hands over ASAP → hectic multitasking without full kit → rework and delays — which add to the uncertainty.
five of the nine self-reinforcing loops mapped in Goldratt's Rules of Flow — dosage, segregation, standardization and resource segmentation complete the set
Formalized by Efrat Goldratt-Ashlag from Eli Goldratt's TOC body of knowledge, built for multi-project environments. Each rule breaks one of the vicious cycles.
Concentrate resources on the most valuable projects and strip out nice-to-have work. Every effort must contribute directly to the goal — and "no" becomes a management word again.
The more projects open at once, the longer every one takes. Cap the number of active projects so each gets enough attention to actually move.
Start a task or project only when everything needed is in hand — specs, materials, decisions. Nothing stalls a stream like discovering mid-flow that a piece is missing.
Give each task a proper dose of attention instead of slicing everyone across everything. Work done in too-thin doses keeps coming back for more.
Starting a project earlier doesn't finish it earlier — it adds WIP and delays everything. Release new work only when resources and prerequisites are ready.
Protect the critical path with pooled buffers, absorb uncertainty where it counts, and verify readiness at gates before work moves to the next stage.
The rules set the flow; Critical Chain Project Management is the mechanism that holds it in place, day after day.
Halve the task estimates and move the margin into one project buffer at the end of the critical chain — plus feeding buffers where branches join. Per-task safety evaporates; pooled safety protects the date.
The plan distinguishes constraints from non-constraints. The critical chain — not each task's own deadline — determines the end date. It is not important that every task is on time; it is essential that the project is.
Rule 05, operationalised: only when a project exits the critical integration point is the next one released. Completion triggers release — not management pressure.
Red-amber-green on the buffer is the single priority signal across all projects — the antidote to the synchronization cycle. The same signal for every project manager and every resource.
Overloaded portfolio? Freeze the lowest-priority ~25%, redirect the freed people to running projects, and defrost in priority order as the drum allows.
Once due-date performance passes 95%, reliability itself becomes a competitive edge — and early delivery the next one, priced where finishing sooner has monetary value.
Project environments where Critical Chain made the difference.
The first Belgian satellite, and ESA's first fully autonomous spacecraft — built in 3 years at a fraction of the conventional budget. Critical Chain brought more stable planning, clear priorities and better risk management. The satellite launched and exceeded expectations.
Read the Verhaert Space case →Critical Chain for large European projects, starting with the VIALFLO technology conversion — technical and marketing work synchronized. The project was delivered before its planned due date; Baxter continues to use Critical Chain for most of its European projects.
Read the Baxter case →That's the bad-multitasking cycle at work. In a first working session we'll map which obstacles are damming your project stream — and which rule breaks each one.
Book a working sessioninfo@leonard.eu.com · +32 3 448 06 15 · Kontich, Belgium