"It is sadly one of those rules-of-thumb numbers that everyone in the industry uses, " she says.

WSJ: Who Makes the Call at the Mall, Men or Women?

One of the problems that I think is plaguing the modern economics and political economy discussion is that as economics professors we have mistakenly ingrained into our students some rules-of-thumb that are coming back to haunt us.

FORBES: How to Grow an Economy

Appropriate for a species that is both predator and prey, System One lives in a world of snap judgments, extensible metaphors, ill-informed biases, and loosely constructed rules of thumb.

FORBES: Thinking Fast, Slow And Not At All