Dan Pfeiffer: “Riding the pollercoaster is an exercise in insanity. A few things to keep in mind (I like to reiterate these reminders every month or so): first, polling is an inexact science. There is a margin for error. A poll that shows Harris up two and one that shows her down two are essentially the same.” “Second — and I can’t emphasize this enough — polling is not supposed to predict the future.