We know that the Patriots yielded the fewest points among NFL teams. But that doesn't mean New England had the No. 1 defense. Going by yards against, it was No. 8. Using Outsiders' DVOA (defense-adjusted value above average), Mr. Stuart notes that the Pats were No. 16 -- mediocre, in sum -- in that metric. He also writes:
"The Patriots faced by far the easiest schedule of any defense in the NFL. New England’s strength of schedule was -7.1%, while Tennessee was 31st at -4.2% and the Bills were 30th at -3.0%. The Patriots would be tied for eighth in DVOA if that metric was not adjusted for strength of schedule, which is why the defense falls to 16th with those adjustments.