President Obama and Mitt Romney squared off in their second presidential debate Tuesday.

Before I jump into the snap polls from after the debate, it’s worth remembering what it means to “win” a debate. It means that voters come away afterwards more likely to vote for you than your opponent. In the end, that’s the winner of the debate.

For instance, Public Policy Polling conducted an instant poll after the debate last night in Colorado and found that 48% of voters declared Obama the winner while 44% of them gave it to Governor Romney. So a slight win for Obama right? Wrong. You can read it that way but that’s not very useful. The same poll found that 37% of voters were more likely to voter for Obama after the debate and  36% more likely to vote for Romney. That’s a tie.

Now, I expect this debate to offset some of the ground Romney gained in the first debate. If that’s the case, then Obama did win. But based off individual polls, if voters are equally as likely to vote for Obama and Romney after last night’s debate as they were before it, then the debate is a draw.

As for the CNN poll that found a 46% to 39% advantage for President Obama, it also is a bit misleading. The poll also found “[o]ne-quarter of debate-watchers said the event made them more likely to vote for Obama, and an equal amount said it made them more likely to vote for Romney. Half said it would have no effect on their vote.” Once again, a draw.

I haven’t been able to find more details on the CBS poll that gave Obama a 37%-30% victory.

The main point is that it doesn’t matter who voters say won. It matters who they are more likely to vote for after the debate. The initial (and likely very noisy) polls indicate that Obama and Romney tied last night. I actually don’t think this is the case – I do think the President won and it will show up marginally in the polls the next few days. Just keep this in mind as you read more polls on “who won” last night. (Image via)