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.
[The good news is the Saints score a lot of touchdowns. The bad news is they do not settle for many field goals. That is why Hartley made 57 extra points last season but only had 22 field goal attempts. Hartley is worth sticking in your lineup when you need a kicker but it is hard for fantasy owners to rely on him consistently because he does not get enough opportunities from week-to-week.]