Adam Schaeffer explains the science of persuasion in a documentary about the cutting edge of US political strategy and tactics.

Experimental designs are like asking a Genie for a wish. You’ll be sorry if you don’t word it carefully.

Let’s say we want to know whether cable ads targeting specific segments of the population or online pre-roll ads are more effective at moving voters’ preferences. To explore this hypothetical, our campaign takes a chunk of money, splits it in two, and tells the TV and online guys to spend it however they want.