Notre Dame QB Comparability: Ian Book vs Jack Coan

Notre Dame has to replace the quarterback Ian Bookwho started 34 of the last 35 games for the Irish. The likely replacement for the book will be the former Wisconsin Caller Jack Coan. The former badger missed the 2020 season after leading Wisconsin to the Big Ten title game and the Rose Bowl in the 2019 season.

I wanted to break down the two quarterbacks and compare their production, their skills and show the differences that Coan will put on the offensive.

First, let’s look at the 2020 season production of Book and the 2019 season production of Coan, his last on the grid. (all data from Pro Football Focus)

Book production came in 12 games while Coan’s came in 14 games. Notre Dame went 10-2 from Book last season while Wisconsin went 10-4. Book and the Irish went 2-2 against senior opponents, while Wisconsin went 3-3 against senior opponents.

Here are the comparisons between Book and Coan with the deep ball (throws that are at least 20 yards beyond the limit).

Deep ball

Coan completed the deep throws at a significantly higher rate than Book, had three more touchdowns on deep balls in nine fewer attempts and a significantly higher passer-by rating.

Here are the comparisons to intermediate trials (litters that are between 10 and 19 meters beyond the limit).


Coan’s completion rate on these throws was nearly 10% higher than Book’s, and his yards per completion per attempt were much higher, as was his passerby rating.

Here is the comparison of all the litters that were at least 10 meters behind the border.

Deep + Intermediate

Book tried far more throws than Coan, but Coan was far more successful. His completion rate was nearly 10% higher, his yards per completion rate were slightly higher, and his yards per attempt were dramatically higher, as was his passerby rating.

If you compare Book’s 2019 numbers to Coan’s, they were a little closer. Book completed 50.4% of his attempts past 10 yards, averaging 24.1 yards per completion and 12.2 yards per attempt. His passerby rating was 186.22.

Not as good as Coan’s, but certainly closer.

Buch was better with throws between 1 and 9 meters after the line.


Coan also had better numbers under pressure.

Coan – 53.1%, 7.4 yards per attempt, 13.9 yards per completion, 4 TD, 2 INT
Book – 49.5%, 6.6 yards per attempt, 13.4 yards per completion, 5 TD, 1 INT

Where Book clearly separated from Coan was as a runner. Book completed 485 yards and nine touchdowns last season, while Coan only completed 22 yards and four touchdowns in 2019. Part of that is how the system works, but Book is certainly a better athlete and runner than Coan.

Here’s how I compare their skills:


There are two ways of assessing arm strength and throwing the ball across the field. The first involves the ability to propel the ball across the field of play. Here I give Book the advantage.

One area where I tend to disagree with most of the analysis I see or hear about Book is about his arm strength. Book can make all the throws a quarterback must, and he can drive the ball down with more authority than Coan.

Where Coan is better as a deep ball thrower, he is a more confident deep ball passer, he throws with better timing, and he throws with better accuracy on most deep throws. But Coan can’t get the ball over defense as Book could, though Book rarely took advantage of this poor talent.

advantage: Even


Accuracy involves more than just completion rate. The problem with using the completion rate is that it can be partially determined by the system. When a crime triggers significantly deeper throws or a higher screen volume, the overall completion rate changes.

The other aspect of accuracy is the ability to place the ball where you want it to be.

Book is a slightly more accurate deep ball thrower when actually shooting, partly due to his advanced arm strength. The problem is, Book was off target and doing deep balls at a slower pace because his timing was much worse than Coan’s and that resulted in him being more off target.

Coan is more accurate at making deep throws, but he may be a little off target on some deep throws that require more force.

Coan is the more accurate thrower at medium and short throws, and he often had to throw much, much narrower windows than Book because Coan was throwing at less effective and talented weapons.

advantage: Coan


This category includes things like reading progression skills, timing as a passerby, anticipation, and the ability to manipulate the defense and handle the bag.

Book has the advantage when it comes to getting out of your pocket and playing with your legs, and that’s a significant advantage. Coan also has advantages, including better reading of the pressure and quick and accurate retrieval of the ball.

Where Coan has a significant advantage over Book, the rest of the categories. He is consistently a better decision maker while also completing a complex crime from a reading standpoint. His timing is better, he expects much better (which means opening receivers more effectively), he is a much more aggressive passer-by (willingness to throw in narrow windows), and his ability to manipulate the defense with his eyes is far better than what we saw from the book.

Both have their problems in their pockets, but Book put in more pressure than Coan. Far too often, Book either got out of his pocket too early or fled outside when the protection was meant to push edge breakers out, which meant he was under pressure. Coan’s problem is that he’s done more backside hits than Book, which sometimes tells me he doesn’t see big backside rushers either.

advantage: Coan

There is a video from the Irish Breakdown Football Analyst at the beginning of the article Vince DeDario and I break down Coan’s game. You can also listen to this analysis in podcast form below.

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