How to make a baseball line

[Spraguer]

Thought I would submit something (unsolicited by Bloggy this time!) for discussion.

Here are the formulae that I use to get from raw numbers to lines, if anybody cares.

You need four numbers to work with: visitor runs, home runs, visitor runs allowed, home runs allowed.

Let's take a look at tonight's Yankees/Jays game with Jaret Wright and A.J. Burnett. I've deliberately picked a game that was a no-play for me (I didn't find enough value on either side).

Specifically for tonight's lineups:
I have the Yankees at 5.27 runs scored, 4.64 runs allowed.
I have the Jays at 4.81 runs scored, 4.02 runs allowed.

First, I need "single winning percentages". For this, we first use Bill James' Pythagorean method. The formula is (A^1.83)/((A^1.83)+(B^1.83)), where A is runs scored B is runs allowed. We can do this for each team to figure out the quality they are bringing to the game. The Yankees get a .558; the Jays get a .621 AFTER adding .040 to the Jays' for being at home.

We use another formula of James', Log5, to get from these winnig percentages to probabilities of winning the particular matchup. The Log5 formula is (C-(C*D))/(C+D-((2*C)*D)), where C is the visitors' pythagorean number from the equation above, and D is the home teams'. For the Yankees in tonight's game, I got .435. 1 - .435 = .565, which is the Jays probability of winning.

So, assuming that the four numbers that we started out with (our handicapping) are correct, the Yankees have a .435 chance of winning the game; the Jays have a .565 chance.

So, let's make a line.

The formula is (1-X)/X, where X is the underdogs win probability. So in this game, the equation is (1-.435)/.435 = 1.30. So, the line is 130. Looks better as a dime line, I suppose:

Yankees +135
Jays -125

How much value you need to play is up to you.

[Domer]

What if you have a pitcher that was just called up...is it a no play by default since they were not a contributor to the current statistics?

[Colemanator]

Put me down for $5000 on both

[Spraguer]

LOL Coleman. Typo, that's Jays -135, Yankees +125.

Domer, what current statistics?

[Domer]

Well I'm just wondering how you would do it with let's say a pitcher was just called up from AAA. He would've had nothing to do with the Runs Allowed statistic thus far in the season.

[Spraguer]

Domer, I'm just saying how to make a line if you've already determined those numbers. That part is up to you. A good place to start on pitcher handicapping is Bloggy's "let's try something this week" thread.

[blogguy]

Thanks for posting the formulas Spraguer. And unsolicited at that!

I remember how I'd felt like I'd discovered uranium or something 20 years ago when I realized that Pythagorean projections could be turned into moneyline equivalents since both can be expressed as winning percentages. An early peak I'm afraid...

Domer, one thing to consider is to just caclulate a "typical" replacement call up starter and plug in the numbers from that. You can always tweak the data if you think the call-up is likely to enter the league with authority (say, a lefthanded strikeout pitcher...the toughest type of pitcher to hit if you've never seen him before)...or if the call-up is just a desparation fill-in (righthander with poor minor league stats and a low strikeout rate).

That should at least get you in the neighborhood. I'm often surprised by how little difference there is between a call-up and the worst guys that are already in rotations. Heck, most call-ups are going to be better than 10-20% of the starters already getting regular work I'd bet.

And...Spraguer would probably point out too that you've got to look at the leveraged bullpens. If teams have lousy relievers, they're extremely likely to get into action when a new guy starts just because new guys typically go 5 innings or less...6 at the most normally. A new guy represents a 7 inning danger spot rather than a 5 inning danger spot on some teams.

[SlipperyPete]

You are absolutely right Bloggie.

I dont even wanna add up how much I lost to callups.

Actually now it is a rule of mine (break it sometimes tho) to not bet against callups
(It could take like a couple of at bats for the hitters to figure him out and by that time the pitch count might be high and they replace him)

I am kinda refining it.
If the callup has ERA (in the minors) under 3.00---I do not bet against him

If he has over 4.5----than maybe



Thanks Spraguer for sharing!!!!!

[Hoppy]

Thanks Spraguer,

[kahlmyishmael]

<div class="FTQUOTE"><begin quote>Originally posted by: Spraguer

Domer, I'm just saying how to make a line if you've already determined those numbers. That part is up to you. A good place to start on pitcher handicapping is Bloggy's "let's try something this week" thread.</end quote></div>


First class work there, Spraguer....might want to note the difference between the average team-in-the league RS/RA/HRH/HRA....

..then note the specific distance between an average MLB team and the pertinent team's strength....

..i guess what I'm trying to do is to adjust it for strength of opposition