In order to answer the question, the measurement of effective and less effective Special Teams units first had to be created. To measure the best coverage units, the average net (total yardage after returns) length of both punts and kickoffs were measured by team and then divided by two to get a basic average score per team. The same was done for kickoff and punt return units to calculate a basic average net return score by team.
For coverage units, the five best team scores were, in order, Denver (52.7), San Diego (52.7), Detroit (52.3), Tennessee (52) and Cleveland (52). The five worst, in order, were Washington (47.05), San Francisco (48.1), New Orleans (48.25), New York Jets (48.40) and Minnesota (49.1). Pittsburgh was 22nd at 49.55.
For return units, the five best team scores were, in order, Cleveland (19.4), New England (18.75), Baltimore (18.2), New York Jets (17.9) and Buffalo (17.85). The five worst, in order, were Carolina (11.65), Cincinnati (12.95), St. Louis (13.60), Green Bay (13.75) and Denver (14.05). Pittsburgh was again 22nd at 14.8 (their punt return average is second worst in the NFL).
Yet, what do these rankings mean in terms of their effects on defensive and offensive effectiveness?
Surprisingly, at first glance, seemingly very little.
Only two of the top five coverage units are on teams with a top ten defense (Denver and Cleveland). The second best is on a team with the 15th worst defense (San Diego), the third and fourth on teams with the 26th and 28th worst defenses (Detroit and Tennessee, respectively). Conversely, of the five worst coverage units, the fifth worst has the NFL's seventh best defense (Minnesota).
Of the top five return units, only one (New England) has a top ten scoring offense. Of the five worst return units, the second worst (Cincinnati) has the NFL's fifth best offense.
So, at first glance, it would appear that Special Teams impact offenses and defenses very little over the long run. Of the top 10 defenses, only 3 have top 10 coverage units. Of the top 10 offensive units, only three have top 10 return units.
Take for example Pittsburgh, whose return unit is 22nd of 32 teams – with a combined punt-kickoff return average of 14.8 yards. The NFL average is 15.81. While Pittsburgh's 10th worst in the NFL, it's only about one yard below average. Is that yard really significant?
Pittsburgh's coverage unit is also 22nd of 32 teams - with a net return average of 49.55 (net punt average is 11th in the NFL at 36.2 net yards per punt and net kick return average is 24th in the NFL at a net of 62.9 yards per kickoff).
The NFL average was 50.50, so Pittsburgh was again one yard below the league average.
So, Pittsburgh's average is just one yard less than the NFL average. Can this be accurate – just one yard lesser than the average NFL team?
The numbers don't lie – but they can mislead. Digging deeper, we can see that Pittsburgh has actually been very solid in its return coverage most of the time. Most of the time. But you see, when Pittsburgh errs on Special Teams, it does so in a big way. While some teams' coverage averages are only slightly better than Pittsburgh's on average, its how they gave up those yards that matter. Better coverage units are consistent – whereas Pittsburgh's may do quite well very often, but then let up a big return that costs the team points and momentum.
Pittsburgh has let up nearly one 45+ yard return per game; eight now in ten games. Compare that with the better Special Teams units like Denver and San Diego, who have given up just one and two 45+ yard returns, respectively.
Pittsburgh has also had just one return this season over 45 yards - that by Sean Morey, of all players. Better return units like Cleveland, New England, Baltimore and Buffalo have had three, four, four and five, respectively.
In the end, what we're seeing is the same underlying issue that's been the concern across the Steeler team in 2006 – consistency and focus. Whether due to over-aggressiveness or lack of discipline, Pittsburgh's Special Teams have performed well for the most part, but have been inconsistent and allowed big plays much more frequently than most other teams have. While their averages are not poor in the aggregate, it's the big plays that have hurt the team, much like what's happened to the passing defense.