Turnover differential played a leading role in the 2011 San Francisco 49ers' success.
It helped them swing field position in their favor.
As the 2012 season approached, the 49ers themselves wondered whether their strength in that area would be sustainable. The 2011 team was plus-28 in turnover differential, after all. History said that would be difficult to repeat. It has been.
49ers Through Seven Games
The 49ers are plus-two in turnover differential through seven games, a big drop from the plus-10 differential they enjoyed through seven games last season. Their opponents' average drive starts have been from their own 26-yard line, same as the average through seven games last season.
The 49ers have a similar record (5-2, compared to 6-1 last season). Their scoring is down from 26.7 to 23.6 points per game. Points allowed have also dropped, from 15.3 per game through seven games last season to 14.3 this season. Yards allowed are way down, from 329.1 per game through seven games last season to 272.3 per game this season.
When using ESPN's expected-points metric, explained here, the 2012 defense grades out roughly the same through seven games at minus-28.8 points this season. The figure was minus-30.9 points through seven games last season. Both ranked among the league leaders.
There are other variables, of course. The team has played a different schedule this year. The offense is averaging 6.1 yards per play this season, up from 5.2 per play through seven games last season.
Overall, though, the drop in turnover differential hasn't been fatal for the 49ers. Far from it.