deliberate vs. emergent strategy
For example, Christensen cites business scholars Henry Mintzberg and James Waters, who in 1985 published a paper defining two forms of strategies: deliberate and emergent. A deliberate strategy, they explained, is a roadmap that a company or an individual puts in place and sets out to follow. An emergent strategy involves the decision to follow a new path when opportunity knocks unexpectedly, or when an unexpected roadblock arises. In work and in life, the question is always which path to take.
To help answer that question, Christensen recommends a tool called "discovery-driven planning," created by Ian MacMillan, a professor at the Wharton School, and Rita McGrath, a professor at Columbia. In the interest of simplicity, How Will You Measure Your Life? distills the tool to a single question: "What assumptions must prove true for this plan to work?"
Listing your assumptions about a prospective plan and assessing their plausibility can help determine the likelihood of a successful outcome, Christensen says, whether you are evaluating an executive decision or a family matter. "Whenever you implement something, if it fails, then almost invariably it did so because there was an assumption in there that, looking back on it, clearly was not plausible," he explains.