Rating the Ratings: If there was a "winner" in the weakening Fox animation world in 2014-15, it was old hand The Simpsons, which had its highest Plus in over a decade. However, like with Family Guy, Fox came about it somewhat artificially. The 4.0 premiere, which probably picked up some heat from anticipation of the Family Guy crossover later in the night, was huge. Though it was not as inflationary here as it was for Family Guy, it made up for much of that difference by airing even more of its fall episodes than usual (six out of eight) with the NFL lead-in. (And, of course, the NFL lead-in becomes stronger in Plus every year.)
Once the dust settled in the spring, it was clearer that the show was weakening, though not quite as much as Family Guy. (From March onward, its average year-to-year decline was in the upper teens, while Guy's was over 20%.) This marked the first time since Family Guy's first full season post-resurrection (2005-06) that The Simpsons had the higher average of the two. Grade: C+.
Here's the now updated War of 18-49 post for The Simpsons.