Evidence: not directly tested

• Circle of competencetype: mental model · evidence: not directly tested

  You don't have to know about everything, just exactly where your knowledge ends, and decide within that boundary.

• First-order negative, second-order positivetype: mental model · evidence: not directly tested

  The immediate consequences of a decision (first-order) often pull in the opposite direction from the ones that follow them (second-order).

• Pareto principletype: mental model · evidence: not directly tested

  In many fields, a few causes produce most of the effect.