Players rise and fall in performance from year to year, and not one person can tell you who will be the next great player. Experience will guide you on how other owners may respond to certain circumstances, yet it can't tell you who's going to win next Monday Night. Well, not until Tuesday at least. Yet smaller leagues require you to gather the most talent onto a small squad as possible because everyone else's squad is just as good. There are Dynasty Leagues, Auction Leagues, and even leagues that once you draft you are done for the year.
Statistics are a tool to determine quantitative numbers and to analyze trends.
But not all math majors make great Fantasy Football owners. Knowing that a running back runs better on carpet that has artificial blades one and a quarter inch tall and that he's playing against the number 22 run defense in the league, may be all well and good when figuring out who to start for the week. But statistics can't always correlate to the fact that he has turf toe or that he had to sleep on the couch last night. Statistics can't take into account the physical, mental and even spiritual wellness of a given player come game time. It's hard enough to find a person that is well versed in any of those categories, let alone all of them.