Theory of Change An Essay by Aaron Swartz www.aaronsw.com A theory of change is the opposite of a theory of action — it works backwards from the goal, in concrete steps, to figure out what you can do to achieve it. To develop a theory of change, you need to start at the end and repeatedly ask yourself, “Concretely, how does one achieve that?” changegoals
Economy of material and labor Whatever the comparative merits of [various bed framing methods], what is clear from Aristotle's Mechanica is that economy of material, and labor, was as much an issue in ancient times as it is now. Henry Petroski, The Evolution of Useful Things The requirements of economyThe art of not constructing simplicity