I was talking to another MFN owner that I respect a lot (respect enough not to name names), and who has beaten me pretty consistently, and I realized he didn't know how the offensive plays were actually called using the play matrix. And if he doesn't know, then I figure a lot more people don't.

So … here we are.

<I would normally insert additional guides I've written here, but I'm too lazy to look them up. Punisher can link them later.>

How does this play matrix thing work anyway?

The Problem
The problem with the play matrix is that it is seductively simple. You just set your percentages, and then at the end of a game or season, your number of play calls will equal the percentages that you set forward. Right? No.

You shouldn't think of the play matrix in terms of percentages, but in terms of ratios. Let's say you want to throw 70% on a particular down and run 30%. You get very clever and say you don't want to throw short more than 50% of the time, so you set that to 50%. You want to have an equal chance to run inside or outside, so you set those to 15%. And you split the remaining 20% between medium and long with 10% apiece.

Your game plan looks like this:

50% - Short
15% - Inside
15% - Outside
10% - Medium
10% - Long

Then you go through a full season and you end up passing 60-66% of the time on that down and running 33-40%. You write a bug report. Curse JDB. Question your fourth grade math teacher. Put numbers into a spreadsheet. Bang your head on the desk. Because you just got ratio'ed.

What happens here is that you have a 50/50 chance to pass short or do something else on the down. It's the something else that gets most game planners.

If you don't pass short, here's what your play matrix looks like:

30% - Inside
30% - Outside
20% - Medium
20% - Long

That means you actually have a 60% chance (4:6) to run if you do not pass short. This means that your ratio is actually closer to 5:3 than it is 7:3. (I'm doing approximate math here, so let's not quibble.)

The Solution
The solution here is that if you want to run or pass for a fixed percentage on a given down, you have to maintain your ratios past the primary thing you want to do on the down. So if you want to pass 70% of the time, but you only want to pass the ball short about 40% of the time, you find your starting ratio.

Remember there are two running play types, so you need the cumulative of those to balance against the short pass type:

42 Short Pass : 18 Inside+Outside Run (9 each)

This leaves you 20 each for Medium and Long passes, which coincidentally, is pretty dang close to the 7:3 ratio when taken as a cumulative of those two passing types against the two running types.

What now?
If you want to game plan in set percentages, think in terms of ratio and not percent.

Bonus FYI
The article that spurred the discussion was this one from 538 from back in January: https://fivethirtyeight.com/features/you-called-a-run-on-first-down-youre-already-screwed/

If you aren't following 538 for your sports news already, you're missing out.

Seriously, take all of setherick's posts and place them in a sticky :)
Thanks for all you do, señor seth.