Campaigns fail if they waste resources courting voters who are unpersuadable or already persuaded. Their most urgent task is to find and persuade the few voters who are genuinely undecided and the larger number who are favorably disposed but need a push to actually vote.

Breaking tasks down into smaller sub-tasks can be very useful.

Solyndra's failure isn't a reason for the government to give up on alternative energy, any more than the failure of Pets.com during the Internet bubble means that venture capital should steer clear of tech projects.

The smartest groups, then, are made up of people with diverse perspectives who are able to stay independent of each other. Independence doesn't imply rationality or impartiality, though. You can be biased and irrational, but as long as you're independent, you won't make the group any dumber.

Unlike most government programs, Social Security and, in part, Medicare are funded by payroll taxes dedicated specifically to them. Some of the tax revenue pays for current benefits; anything that's left over goes into trust funds for the future. The programs were designed this way for political reasons.

In order to work well, markets need a basic level of trust.

Traditionally, tours were a means of promoting a record. Today, the record promotes the tour.