One-third of voters say the presidential debates will be very important in helping them decide whom to support for president, with slightly more Republicans than Democrats saying so, a new Wall Street Journal/NBC News poll has found.
This is one reason not to take polls too seriously. It’s not even faintly plausible that a third of the voting public is undecided enough that the debates will make any difference to them. The true number is probably closer to 5 percent. Maybe 10 percent at the outside. And even that small number will probably break about evenly by Election Day. There’s an endless body of research showing that the actual effect of debates is minuscule.
In most polls,1 the fact that people say stuff like this is a far, far bigger source of inaccuracy than the margin of error. The biggest problem with polls is human beings, not statistics.
1Simple candidate preference polls are an exception. They tend to be fairly accurate.