FiveThirtyEight ’s homebrew “ Polls - Plus ” model , which weights several factors based on a secret formula , has been worse at predicting outcomes than a weighted average of the most recent polls . It ’s hard to pin down Silver ’s actual success rate when these two models compete with his third demographic model , which in turn might contradict his blog posts and podcasts . Benchmark Politics , an upstart competitor that claims its record is better than FiveThirtyEight‘s , likens Silver ’s hedging to “ telling a basketball team they can shoot four free throws movement.transportartifact.nonviolentthrowlaunch instead of two . ” Even when all of Silver ’s models for a given race turn up wrong , it never seems to be FiveThirtyEight ’s fault . When the site badly whiffed on last year ’s British election , it was the pollsters who erred .