Three big economics ideas: Mankiw's, Steckbeck's, and mine

Greg Mankiw lists his favorites for "three big economic ideas". Mark Steckbeck's list is better. Mine is very close to Steckbeck's, just a little different wording and emphasis:

1. People tend to respond to incentives.

2. Scarcity, and its important corollary, opportunity cost.

3. Markets tend to be low cost allocators of goods and services.

(I'd put "Voluntary trade is mutually beneficial" at #4.)

UPDATE: Steckbeck link is now correct. Thanks to reader Michael W. for pointing out the error.

Comments

[Michael W. Kruse]

You've got Mankiw linked twice here. I think the Steckbeck article is:

http://liberalorder.typepad.com/the_liberal_order/2007/08/the-top-three-e.html

Thanks!