49ers fourth down tendencies in 2014, and what coaching change could mean in 2015

Football Outsiders released their 2014 Aggressiveness Index, and the San Francisco 49ers ranked just a shade above middle of the pack. The index measures fourth down tendencies that was relatively easy to understand, but accounted for the different rates in which teams went for it on fourth down.

The index centers around 1.0, and describes how much more or less a coach is likely to go for it on fourth down compared to other coaches. A 1.2 AI means the coach is approximately "20 percent more likely to go for it than an average coach in equivalent situations. It excludes catch-up situations, which FO describes as "third quarter, trailing by 15 or more points; fourth quarter, trailing by nine or more points; and in the last five minutes of the game, trailing by any amount."

Jim Harbaugh finished at 1.08, which means in 2014 he was roughly 8 percent more likely to go for it than the average coach. Sean Payton led the league at 2.01 (101 percent more likely), while Dennis Allen was at the bottom, never going for it on fourth down before he was fired. Mike Smith was at the bottom among coaches who made it through the entire season, finishing at 0.21. So he went for it 79 percent less than the average coach.

It is worth noting, FO recognizes the formula still needs some tweaks. It does not control for teams being naturally conservative with late leads, or teams in tie games late, where a field goal to win it makes more sense than going for the conversion. It is all part of the learning process.

The 49ers made significant changes across the coaching staff, but I find myself thinking we might see a more aggressive team on fourth down. Statistical analysis indicates teams should be going for it more on fourth down, particularly on fourth and short situations, and situations on the opposing team's side of the ball. Coaches are frequently content to take the three points, or punt to pin the other team deep.

The 49ers team president, Paraag Marathe, is a big proponent of advanced analytics. With Jim Tomsula potentially more "friendly" to what the front office is looking to do, could we see a team that is more aggressive on fourth down?