The Five Decision Dimensions

Build-vs-buy decisions in AI are more complex than in traditional software because the ecosystem moves faster. A capability that requires 6 months of internal development today may be available as an API next quarter at a fraction of the cost. Conversely, a vendor solution that works today may be deprecated, repriced, or acquired by a competitor next quarter. The VANGUARD build-vs-buy framework evaluates five dimensions: strategic differentiation (does this capability create competitive advantage?), total cost of ownership (what does each option actually cost over 3 years?), time to value (how quickly does each option deliver value?), vendor dependency risk (what happens if the vendor changes terms?), and ecosystem trajectory (where is the ecosystem heading — toward commoditization or specialization?).

1. Strategic Differentiation Capabilities that differentiate you from competitors should generally be built. Capabilities that are table stakes should generally be bought. If your competitive advantage depends on a unique AI model fine-tuned on your proprietary data, build it. If you need a standard chatbot framework that every competitor uses, buy it. The test: would losing this capability to a vendor outage eliminate a competitive advantage?
2. Total Cost of Ownership Build costs are consistently underestimated by 2-3x because organizations forget to include ongoing maintenance, infrastructure, monitoring, security patches, and the opportunity cost of engineering time. Buy costs are consistently underestimated because organizations forget to include integration, customization, migration costs, and the inevitable pricing increases. Model both options honestly over a 3-year horizon with contingencies.
3. Ecosystem Trajectory This is the dimension that most frameworks miss. If the ecosystem trajectory is toward commoditization (open-source catching up, prices declining, multiple vendors converging on similar capabilities), buying becomes more attractive over time — today's premium vendor solution will be tomorrow's commodity. If the trajectory is toward specialization, building may be necessary because no vendor will serve your specific needs.