American Football

Remembering that narratives =/= truth: Jimmy Garoppolo’s CPOE as a case study

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Remembering that narratives =/= truth: Jimmy Garoppolo’s CPOE as a case study
Kelley L Cox-USA TODAY Sports

Over the past few decades, general public interest in the National Football League has exploded. Due to this, a sport that is played for 5 months a year (September through February) is covered for 12 months a year. As reporters, sportscasters, and talk show hosts have jobs to do, stories get told and in some cases a story can be told so many times that we begin to assume it is true. However, that isn’t always the case and it is important to keep this in mind as the offseason rolls around and players become available.

As a forewarning, by no means do I intend for this article to ‘bash’ San Francisco 49ers Quarterback Jimmy Garoppolo or be perceived as such. In fact, I think a lot of teams could add Jimmy G (as some call him) and see a major improvement over their current QB, and for that reason Jimmy G deserves every dollar he can get on his next contract, which should be a large amount. Instead, what I am intending is for this article to serve as a reminder that somethings reality and the narratives we have been told do not align. In support, I give the completion percentage over expected (CPOE) of Jimmy G (as well as Brock Purdy). CPOE is an advanced analytics estimate that is thought to be an improvement over raw completion percentage because it allows us to account for the difficulty of the throws a QB is attempting; a more thorough explanation of this statistic was previously provided by ProFootballFocus. Essentially, this allows us to piece apart the degree to which a QB’s statistical output is due to the supporting cast creating ideal opportunities or excellence on the part of the QB. Using CPOE as his statistic of interest, the below table was created by Tej Seth, a well-regarded NFL analytics poster on Twitter. While I typically opt to embed tweets, the width of the table prevented the table from being fully readable in that format.


Table credited by Tej Seth and full tweet can be accessed at https://twitter.com/tejfbanalytics/status/1615811380031983642

As we can see in this chart, Jimmy G is about as league average is it comes. He has an (essentially) average completion rate on throws ranging from behind the line of scrimmage to under 15 yards, while an almost 10% below expected completion percentage on throws over 15 yards. While an average completion rating is nothing to sneer at, it does not align with the “very accurate passer” narrative that has followed Jimmy G over the past few years.

While none of us can be expected to examine the underlying analytics of every NFL player and commit it all to memory, I think it is important to remember that sometimes the narrative of a player is not the full truth. In the case of Jimmy G, these numbers suggest he will go about as far as the supporting cast around him will take him. For the New York Jets, that may depend on what other additions are made to the offense over the next few months.

But what do you think? Does this table not adequately represent Jimmy G’s quality of play? And what other players do you think have a misalignment between their reputation and their actual play?

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