The data proves Cuccinelli could have won -- if he'd focused on abortion

What moved the voters most was an attack on McAuliffe’s positions on abortion; a single phone message emphasizing McAuliffe’s support for unrestricted, late-term, and taxpayer-funded abortions shifted support a net 13 to 15 points away from McAuliffe and toward Cuccinelli. The cost per vote here was a remarkably cheap $0.50 per additional vote, and even less expensive still when targeting the most persuadable segment of the electorate.

A topic declared radioactive by nearly everyone, locked away in secure storage behind a blazing Hazmat warning by the Cuccinelli campaign, appears to have been a powerful weapon for the Republican ticket that could have substantially closed the gap, and possibly even won Cuccinelli the election.

Here is the fundamental lesson: We do not know what works until we test it, repeatedly, using experiments. Randomized-controlled experiments allow us to block out all the other noise and pinpoint precisely how a message or tactic changes voter behavior. This is key: rigorous experiments randomly assign voters to receive a treatment, or to a control group that receives nothing, or a placebo.