How the method works
A stage-gate process breaks an initiative into defined stages (concept, feasibility, development, testing, launch, or equivalents) with a gate before each. Every stage has deliverables; every gate has criteria and a decision authority; funding is released one stage at a time. The design goal is to spend the least money required to resolve the largest remaining uncertainty.
What it does for the portfolio when taken seriously
Run honestly, stage gates change portfolio economics. Weak initiatives die at early gates, cheaply, releasing money and people while they can still be redeployed, and leadership gains a legitimate way to fund exploration without committing to delivery. The kill rate is the health indicator. A portfolio where nothing dies after the first gate is not blessed with exceptional judgement; it is running an approval pipeline dressed as a filter.