So even at an order of magnitude smaller than the experimental effect, VMP could have serious consequences. “Four to 8 percent would get any campaign manager excited,” says Brian Keegan, a computational social scientist at Harvard Business School. “At the end of the day, the fact is that in a lot of races it only takes a swing of 3 or 4 percent. If the search engine is one or two percent, that’s still really persuasive.”