Primer For Understanding Analytics Recaps and Previews

As we use analytics to better evaluate the 2020 Notre Dame Fighting Irish football team, there are going to be some statistics that you will need to understand the articles we are posting. This list will provide not only definitions of the stats, but some context for what we will use the stats to learn and how it can be made actionable in future weeks by Irish players or coaches.

• Expected Points Added (EPA): This measures the difference in the expected points a drive is worth before and after each play. This link provides an excellent detailed explanation (credit to Alok Pattani and ESPN for the detail). Essentially, it takes into account the down, distance, and yard line among other factors and calculates the expected number of points a team scores from that position. EPA is simply the difference in Expected Points at the start of a play and the end of it.
• Success Rate: Created by Bill Connelly of ESPN, a play is deemed a success if it gains 50 percent or more of the yards required for another first down on first down, if it gains 70 percent or more of yards required for a first down on second down, or if it gains a first down on third or fourth down. This is used to get a sense of how successful a play actually is in the context of the situation, i.e. getting six yards on first and 10 is a successful play, but getting six yards on 3rd and 11 is not.
• Personnel: The first number refers to the number of running backs, the second number refers to the number of tight ends, and the number of wide receivers can be inferred from knowing these two numbers. We do not have access to All-22 film so this is based on alignment at the snap. For example, if Tommy Tremble is lined up in the slot in a receiver’s stance he is considered a receiver and not a tight end.
• Average Depth of Target (aDOT): The number of yards downfield a receiver is when the ball is thrown to them. This is used to get a sense of where on the field the team tends to attack the opponent, and break down a quarterback’s performance to see how well they are controlling various aspects of the game (screen game, deep passing, etc.)
• First Down Rate: The percentage of plays of a given type resulting in a first down.

For fuller context of EPA/play and success rate here are a series of charts showing Notre Dame’s 2019 statistics in these areas, the national leader’s statistics, and the FBS average. Please note that in the rushing EPA/play chart the FBS average is 0.00 EPA/play, so the bar is not missing it is just zero.

As shown, even slightly positive EPAs indicate above average performance, although some elite teams are able to generate points consistently above zero. Notre Dame was far more efficient passing than rushing last season, although the FBS as a whole was only slightly better off throwing than passing. Believe it or not, Alabama, LSU, and Clemson were all pretty good football teams in 2019.

All of these statistics can be used in conjunction with traditional stats to gain a fuller picture of what is going on on the field for the Irish. If you have further questions or want to comment on the positives and limitations of these statistics, please leave a comment and we will be happy to try to expand your analytics knowledge even further!