One of the biggest factors in the Buffalo Bills' being 3-1 through a quarter of the 2011 NFL regular season is the fact that they're performing so well in the turnover battle.
The Bills have forced at least two turnovers in each of their first four games this season, and have taken the ball away 11 times overall. They've committed just four turnovers themselves. Their plus-7 turnover ratio is currently tied for the second-best margin in the NFL, trailing only the 4-0 Detroit Lions and 3-1 San Francisco 49ers (they're tied with the 3-1 Baltimore Ravens).
Buffalo had a four-game stretch last season in which they forced 11 turnovers, but committed 10 themselves in that time frame in finishing 2-2 (with one of those losses being the heartbreaker to Pittsburgh). In 2009, the Bills had a four-game stretch in which they forced 14 turnovers and were plus-7, but still somehow managed to only win two of those games.
Turnover margin is something of a cliche in NFL circles, but cliches exist because they are fundamentally true. While the Bills iron out inconsistencies offensively and defensively, they must continue to perform well in this department. We saw in Week 4 how a couple of big plays can keep a team getting controlled in every fact in a ball game.