As someone who makes a living analyzing statistics and processes, I greatly dislike anecdotes and conjecture. Among those worthy of fantasy scorn are owners who attempt to validate their personal opinion of a NFL player's fantasy value by pointing to their upcoming season's strength of schedule. Why is this infuriating? Simple: There is very little -- if any -- correlation between the amount of positional fantasy points a team gives up from one year to the next.
Don't believe this? Let's review strength of schedule from last year; specifically, how teams finished last season versus their SOS entering the season. In this case, strength of schedule is defined as the average number of fantasy points scored by a team's weekly opponent at a specific position, analyzed for the full season. Then, we look at the team's preseason and actual SOS rank for each position to see how it changed in terms of the rank of ease.
Note that since the NFL has 32 teams, any change of eight slots or more represents movement of at least 25 percent, which is significant.
Fifteen of the 32 teams, or nearly half, moved at least eight spots (at least a 25 percent differential) between their preseason strength of schedule and their 2013 actual strength of schedule.
Some will point to teams such as the Dallas Cowboys, whose preseason QB SOS was 255.3 fantasy points and their final QB SOS that finished at 254.3 as support for their position, because even though they moved seven slots, from first to eighth, the total points only changed by one point. That is a flawed statistical argument. The league-wide average improved by 7.2 points, which means that despite having a similar starting and ending points for their SOS, they lost ground on the league's SOS and that's what drove their actual SOS drop.
Twenty-three of the 32 NFL teams -- or 72 percent -- had their RB SOS move by eight of more spots. It's clear that RB SOS is extremely volatile.
Wide receiver is the least volatile to SOS fluctuations, but even in this position, 41 percent (13 of 32 teams) have a final SOS at least eight spots different from their preseason SOS.
The tight end position is similar to the wide receiver position in that 44 percent of the teams finished with actual SOS moving at least eight positions from their preseason expectation. If the least volatile of the skill positions (tight end) still has 41 percent of the teams finishing with at least a 25 percent differential between starting SOS and finishing SOS, it's safe to say that preseason SOS really doesn't shape a player's value.