Map the constraint cascade before intervening
Before executing any bottleneck intervention, map the cascade by ranking all workflow steps from lowest to highest maximum capacity, identifying where the next constraints will appear when the current one is removed.
When This Fires
- Before investing significant effort in fixing any workflow bottleneck
- When previous bottleneck fixes produced disappointingly small throughput improvements
- When Optimize only the single slowest step — improvements…'s bottleneck-only optimization needs the predictive dimension
- Complements Re-measure 2 weeks after any constraint fix (post-intervention re-measurement) with the pre-intervention prediction
Common Failure Mode
Tunnel-vision optimization: fixing the current bottleneck without considering the cascade. After weeks of work improving step 2, throughput increases 10% instead of the expected 50% because step 5 was nearly as constrained and immediately became the new bottleneck.
The Protocol
(1) List all steps in your workflow. (2) For each step, estimate maximum throughput: how many items could this step process per period if it were the only step? (3) Rank from lowest to highest capacity. The lowest is your current constraint; the second-lowest is the next constraint in the cascade. (4) Calculate the cascade gap: if you fix the current constraint to match step 1's capacity, what throughput does the cascade produce? This is the maximum benefit of fixing the current constraint. (5) If the cascade gap is small (next constraint is close to current), consider fixing both simultaneously. If the cascade gap is large (next constraint has much higher capacity), fixing the current constraint alone will produce meaningful improvement.