Week 1 in review: Net yardage, Glicko, etc.


It’s not shocking that the Saints lost: they were playing a better team on the road. But it would have been a nice win to have, especially because the NFC South promises to be a competitive, if not stellar, division.

Here are the Glicko rankings after week 1 of the NFL season. I seeded the 2015 rankings with mean-regressed 2014 rankings. In other words, these rankings take last year’s ranking into account, at least a little bit. Don’t forget the rankings are dumb in that they only take a few things into account: wins, losses, consistency, and opponent strength. So if Aaron Rodgers (or, more pertinently, Jordy Nelson) got hurt last week, the Packers’ Glicko rating would not change until they started losing games.

In the chart, teams with green dots are above league average, teams with grey dots are around league average, and teams with red dots are below league average, at least according to the Glicko ratings. Also note that there’s a bug in the code I used to generate this chart, so the Bengals should be green and the Jets should be grey. Sigh.

Week 1 2015 Glicko ratings

Glicko has the Saints right at league-average, in the same ballpark as the Falcons and Panthers and notably better than the Bucs. Sounds about right.

Other graphs

I’ve been playing around with a few other graphs in an attempt to analyze last week’s game. They’re all variations on the theme of how to visualize possessions and field position within a game. I’m not sure how useful they are, but here goes.

This first one I’m calling a Net Yardage chart. It shows the cumulative net yardage for the Saints: a positive net yardage means the Saints have gained more yards than their opponents, a negative net yardage means they’ve been out-gained. These graphs count punts, punt returns, and penalties, but don’t count kickoffs and kickoff returns. Check it out:

Week 1 Net Yardage Chart

This chart shows that Arizona was fairly dominant in the first half: at no point did the Saints have more total yards than the Cardinals. That flipped quickly in the second half when Brees connected with Snead for a 63-yard gain. In all, the second half was much more even in terms of net yardage. The difference: the Cardinals scored touchdowns, the Saints scored field goals.

Here’s another chart I’ve been working on. I’m calling it a Ball Travel chart. It graphs the field position of the ball over time. Each individual line follows the ball as it moves across the field towards the Arizona end zone (marked 100 on the graph) or the New Orleans end zone (marked 0 on the graph). Once a team scores, the chart starts over. This might be more clever than it is informative, but I kind of like it. You’ll probably want to click to enlarge it:

Week 1 Ball Travel Chart

Finally, here’s one I’m calling a Drive Chart. It’s essentially the same as the Ball Travel Chart, but it displays each drive individually, color-coded by team. The dashed grey lines represent punts. Again, maybe more clever than useful, but I’m not sure.

Week 1 Drive Chart

I’m still working on automating these, so I probably won’t produce them every week. But it’s fun to screw around.

Exclusive Week 2 preview!

The Saints are, like, way better than the Bucs. They’d better win.