We've thought about that a lot. There are a number of things that cannot be quantified. For instance, we look at military issues, and we point out that in many instances, how well the president conducted a campaign, if there was a war, made a difference. We have no way of quantifying that.
Which president did the worst?
Well no president did the worst on every single thing, but George Bush Sr. tended to show up at the bottom an awful lot.
Why aren't there more books like this?
Anytime you write something like this, you're going to be called biased, whether you are or not. For instance, on a lot of economic issues, the Democrats tended to do better than Republicans. That was a surprise to us.