Strength of schedule is calculated from the opponents projected fantasy points allowed for the PK position. The best rating is +16 which gives the player the advantage against the defense and indicates an easy opponent, the worst rating is -16 which gives the defense the advantage and indicates a tough opponent.
You will notice a trend at the top of the kicker rankings. A great offense has a top-tier quarterback which translates into a top kicker. With Aaron Rodgers at the helm for the Packers, Mason Crosby will find plenty of success. His struggles of 2012 when he was 21/33 on field goal attempts appear to be a distant memory. In the last two seasons, he has kicked a combined 9 field goals from over 50+ yards.