There are a lot of ways to look at a football game. These are the numbers you won’t find in the ordinary box score.
Each week following the game we’ll be sharing some key stats — many of them based off Bill Connelly’s “five factors” — to track the Huskers’ progress this season. Here’s a quick explanation of each of the categories:
Efficiency (Success Rate)
Success rate is a popular measure in football analytics and essentially shows how often a team is “staying on schedule.” Each down falls into one of two categories: standard downs and passing downs. Standard downs are any first down, second-and-6 or shorter and third/fourth-and-4 or shorter. Everything else is a passing down.
The Football Outsiders’ criteria for a successful play are as follows: at least 50 percent of the yards needed on first down, 70 percent of the yards needed on second down and 100 percent of the yards needed on third or fourth down.
An average success rate is usually around 41 percent on all downs, 46 percent on standard downs and 31 percent on passing downs.
Explosiveness (Yards Per Play)
The first number we look at when we get a box score is yards per play. It tells you quite a bit and serves as the easiest stand-in for an explosiveness measure. It doesn’t tell you everything, however. Occasionally, we’ll also include an “explosiveness rate” which is just the number of explosive plays (defined as plays of 20 yards or more) divided by the number of total plays. All of the yardage stats we use are sack-adjusted, meaning sacks are counted as passing plays rather than rushing plays.
Finishing Drives (Points Per Trip Inside the 40)
This is a simple one: number of points per drive on drives when the offense has a first down inside the defense’s 40-yard line. It’s a little more interesting than simple red zone stats — any team should be expected to get some points inside the 20 — because it introduces some decision making variables from the coaches in addition to measuring a team’s ability to convert most of its scoring opportunities. The goal is simple — touchdowns, not field goals, so the closer a team’s average is to seven points the better, but four is about the breakeven point.
Self-explanatory, but turnovers change games and few teams know that better than Nebraska of late. Simple turnover margin is generally a good indicator of which team won or lost, but we’ll typically use turnover points (measuring the presumed value of a team’s turnovers based on field position and the actual points scored off those turnovers). For example, if Team A turns the ball over on Team B’s 11-yard line, Team A is giving up 5.08 expected points based on field position. If Team B goes down and kicks a field goal, the total value of Team A’s turnover is 8.08 (5.08 expected points + 3 actual points).
Where teams start their drives is often a good indicator of their overall success in a game and encompasses a lot of different aspects of football — forcing or avoiding turnovers, special teams play and decision-making. All of our field position stats are expressed in yards from goal, meaning that an average starting field position of 72.28 equates to starting at about the opponent’s 28-yard line. On average across college football, a team’s average starting field position is around its own 29-yard line.
Points Per Drive
Points per drive is a basic but good efficiency metric that adds scoring — really the only number that truly matters — into the mix. It’s simply total points divided by total drives and a rate of 2.1 points per drive is about average.