Brooks's Law — "adding manpower to a late software project makes it later" — was formulated by Fred Brooks in his 1975 classic The Mythical Man-Month. It explains why the intuitive response to a project falling behind schedule (adding more people) reliably backfires in software development, and often makes things worse. The underlying insight extends to any knowledge work where ramp-up time and communication overhead scale superlinearly with team size.
Cost-Benefit Analysis (CBA) is a systematic decision-making framework that quantifies all relevant costs and benefits of a course of action — including indirect and intangible ones — and compares them to determine net value. It disciplines decision-making by forcing explicit identification of trade-offs rather than allowing them to remain implicit. Widely used in public policy, investment appraisal, project selection, and operational decisions at all levels.
Divide and Conquer is a problem-solving strategy that breaks a large, complex problem into smaller, independently solvable sub-problems, solves each sub-problem, and then combines the solutions. Originating in algorithm design (where it underlies merge sort, quicksort, and binary search), the principle extends to project management, strategic planning, and any domain where complexity makes direct attack impractical.
The Planning Fallacy is the tendency to underestimate the time, costs, and risks of future plans while overestimating their benefits, even when aware of past projects' tendency to run over. Described by Daniel Kahneman and Amos Tversky (1979), it is one of the most costly cognitive biases in project management, construction, software development, and government, and is best corrected using Reference Class Forecasting — anchoring estimates in the historical base rate of similar projects.