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Stats for the 2019 Season

Indianapolis Colts v Tennessee Titans Photo by Wesley Hitt/Getty Images

Each week during the season, I will be walking through the data from the previous Colts game analyzing the numbers to form a sort of “what happened” narrative as well as comparing the Colts against all other teams in the league. This will also include a brief numerical view of the upcoming match-up. The offense will be reviewed on Wednesdays and the defense on Thursdays.

I don’t rely on standard measurements to judge the performance of a team or specific player, preferring instead to use stats that have proven to be the most effective in describing actual and predicted performance. So, while I will publish the standard Total Yards, Passer Rating and Yards per Carry type stats, my analysis will primarily focus on stats you may not be familiar with or even custom stats that I have researched and created.

To help those unfamiliar with that information, this will be a glossary/tutorial/walk-through that documents those stats and will be linked in the weekly articles for reference. I’m not going to go into a huge amount of detail on the stat definitions here, but will provide links to additional information where available.

If you have any suggestions to improve the analysis, please leave a comment.


DRIVE CHART

I will post a custom drive chart to provide a high level visual guide to the flow of each offense (Colts on Wednesday, opponent on Thursday). Here is an example from the IND-HOU 2018 Wild Card playoff game.

Clicking on the image will give the reader a larger view of the image.

The top row of the graphic lists the week, the offense that is being displayed and the opponent along with game outcome. The additional data in the header row is:

  • PPD: Points per drive
  • Drv/Srs/Frst: The number of drives, series and converted first downs (including TDs and penalties)
  • DSR: Drive Success Rate, which is Converted Firsts / Series
  • Exp Off pts/ovr: The Expected Offensive points based on DSR, avg starting field position and average yards per converted series. This is then compared to the actual offensive points (def and special team scores excluded) to calculate the “over”.

The image displays a horizontal bar for the sequence of offensive drives in order from top to bottom. The width of the bar is the total number of yards gained, which is also displayed in white in the center of the bar. All drives move left to right, so that the starting field position is the left most edge of the bar and the right most edge is where the drive ended. The exception to that is negative yardage drives where that is reversed.

The color of the drive bar represents the drive outcome:

  • Green: Touchdown
  • Gold: Successful Field Goal
  • Red: Negative yardage drive
  • Black: A drive ended by time expiring
  • Gray: All others (failed drives)

Overlaying the drive bar are various graphics that represent key events in the drive. These are also described in the legend at the bottom of the image:

  • Dark Blue graphic: Pass play event
  • Purple graphic: Rushing play event
  • Light Blue Graphic: Penalty event
  • Vertical Line: A converted First Down (or TD), placed at the yard line where the play completed.
  • Arrows: A penalty, a negative play or an explosive play (run >=10, pass>=20). Arrows start at the line of scrimmage and end at the yard line where the play completed.
  • S: A sack, placed at the spot of where the sack occurred (not necessarily where the play ended)
  • X: A turnover, placed at the spot of where the turnover occurred (not necessarily where the play ended)

The left side end zone displays the starting time of the drive in minutes remaining, and the starting score differential. The right side end zone shows the result of the drive and the total offensive score after the drive (including defense and special team scores). Outside the right end zone is the Time of Possession and the Pass-Rush split with volume and yards.

Immediately underneath the image, are various game level stats:

  • Yds: Total offensive yards with pass/rush split. Sack yards are included in pass yards
  • Ply: Total offensive plays with pass/rush split
  • EPA/p: Expected Points Added per play.
  • NY/A: Net Yards per passing Attempt
  • 3DC: Third down conversions over 3rd down plays.
  • YTG/3rd: The average yards to gain on 3rd downs.
  • Strt Fld: The average starting field position
  • TOP: The total time of possession

TABLES

There will be three tables with views for passing, rushing and overall team productivity. Each table will also have multiple versions for three different time periods; that week’s game, season totals (after week 1) and trailing 5 week totals (after week 6).

The tables will be sorted using a single representative stat that will always be the first column. This stat is the best metric to describe overall actual performance (but not necessarily future performance).

Stats of higher importance are given a heat map color formatting. The blue heat map columns represent stats that are the most predictive and best describe future play. The other important stats are given a green to red heat map to identify ranking.


TEAM STATS

This is an example of season totals for last year. Clicking on the image will give the reader a larger view of the image.

  • Adj Net PPD: Adjusted net points per drive. This removes drives where time expired and does not include defensive or special team scores. It is only net points that happen due to offensive performance (TD, XP, 2pt Conv, FG, Safety, Turnover TD).
  • PPG: Total Points per game
  • Yds: Total Yds per game (net of sacks)
  • P/R%: Pass/ Rush ratio
  • xOPPD: The Expected Offensive Points per Drive, based on DSR, avg starting field position and average yards per converted series. This is basically what un-adjusted offensive PPD “should have been”
  • xOPPD +/-: The amount of xOPPD over/under actual offensive PPD. Amounts > 0 mean the team “outsored DSR” and achieved more points than warranted for the given DSR, suggesting a regression of points relative to DSR in the future.
  • DSR: Drive Success Rate
  • Strt Fld: Avg Starting Field Position
  • EPA/Ply: Expected Points Added per play.
  • wTSR: Weighted Total Success Rate. A success rate of each play based on EPA over median EPA, weighted by outcome and adjusted for 4th quarter game script. This uses similar logic as the weighted rushing success rate
  • 1st%: Total first downs / total plays.
  • Pen 1st/Yds: Qty and yards of first downs obtained by penalty
  • 3DC: Third down conversions divided by 3rd down plays.
  • 3rd Ytg: The average yards to gain on 3rd downs.
  • Expl Plys: Qty and total yards of rush plays >= 10 yards and pass plays >=20 yards
  • TO: Turnovers
  • TOP: Time Of Possession

While Adjusted Net PPD is the most correlated to wins, my analysis will focus more on xOPPD as that is the most correlated to future wins, so, it will be important for a team to rank well in that stat. DSR and Starting Field position are variable components of xOPPD and will help explain why it is so high/low. Scoring more actual points than expected may not be sustainable so xPPD +/- will be addressed as well.

EPA/ply, 1st% and wTSR are 3 measures that are all highly correlated to game outcomes and so it will be important for an offense to do well in all 3. 3DC is a subset of 1st% and so is not as important, but it can help explain variance in that number and 3rd ytg can help explain hi/lo 3DC.


PASSING STATS

This is an example of season totals for last year. Clicking on the image will give the reader a larger view of the image.

  • EPA/db: Expected Points Added per dropback
  • Cmp: Completions
  • Att: Attempts
  • Yds: Passing Yards (sacks not included)
  • Td: Passing TDs
  • Int: Interceptions
  • Sk: Sacks
  • Sk Y: Sack Yards
  • Rtng: Passer Rating
  • wPSR: Weighted Passing Success Rate. A success rate of each play based on EPA over median EPA, weighted by outcome and adjusted for 4th quarter game script. This uses similar logic as the weighted rushing success rate.
  • 1st%: Passing First Down Conversions / dropbacks (spikes excluded).
  • ANY/A: Adjusted Net Yards per Attempt. (Passing Yards - Sack yards= 20 * Passing TDs - 45 * Interceptions) / (Attempts+ sacks)
  • NY/A: Net Yards per Attempt. (Passing Yards - Sack yards) / (Attempts+ sacks).
  • YPA: Yards per Attempt.
  • Cmp%: Completion %.
  • aDOT: Average Depth of Target. This is the average distance past the line of scrimmage (air yards) that the ball travels on attempts.
  • aYd: Air Yards. This is the average distance past the line of scrimmage (air yards) that the ball travels on completions.
  • YAC: Yards After Completion. The average yardage advanced after the point of completion.
  • 20+(#/Yd): The qty and total yardage of explosive pass plays (passes >=20 total yards)

EPA/db is the best overall stat to measure QB performance with wPSR being just a bit more predictive. 1st% is a critical component of wPSR and few QBs can be successful without a high number there.

I won’t reference passer rating much as ANY/A is the superior version of that stat. Then ANY/A deconstructs into NY/A and YPA by removing INTs, TDs and then sacks.

YPA can be reduced to Cmp%, aDOT, aYD and YAC which are not critical individually, but can help diagnose YPA problems. For example, a low aDOT in and of itself is not a bad thing but low aDOT combined with low Cmp% is going to drive low YPA and can indicate a QB issue.


RUSHING STATS

This is an example of season totals for last year. Clicking on the image will give the reader a larger view of the image.

  • wRSR: Weighted Rushing Success Rate A success rate of each running play based on EPA over median EPA, weighted by outcome and adjusted for 4th quarter game script.
  • Yds: Rushing yards
  • Car: Carries
  • TD: Rushing TDs
  • Fum Lost: Rushing Fumbles lost
  • RSR: Rushing Success Rate. This uses the same success criteria as wRSR but does not weight by outcome or adjust for 4th qtr.
  • 1st: Rushing 1st downs
  • 1st%: Rushing 1st downs / Carries
  • YPC: Yards per Carry
  • 10+ (#/Yd): The qty and total yardage of explosive rush plays (rushes >=10 total yards)
  • 3rd: Converted 3rd downs
  • 3DC: Converted 3rd downs / Carries

The run game is notoriously difficult to analyze as a whole, so I I created the wRSR stat, which at its core is just the weighted frequency of runs that exceed the average run outcome by situation. Key drivers of that will be TDs and rushing first downs, which are highly impacted by 3rd down conversions.