How do you figure out FIP and .SLG?

[billyhallfan]

I am not real stat savy, I only know the basic stuff.

 

I know that .SLG % is out of .4000, but how do you figure it out, and could someone please explain FIP?

[1992casey]

Slugging percentage is total bases divided by AB.

 

A batter gets one total base for a single, two for a double, three for a triple, and four for a homer.

 

You can do this:

 

SLG = Singles + (2*2B) + (3*3B) + (4*HR) / AB

 

But this is easier:

 

SLG = Hits + 2B + (2*3B) + (3*HR) / AB

 

The reason the second one is easier is that most stat pages list total hits but not singles. You're saving yourself the bother of subtracting doubles, triples, and homers from the total number of hits to get singles.

 

Note that the formula for total bases in Brewerfan.net stat glossary is wrong. It'll have to be corrected eventually.

 

I'll quote the Hardball Times Stat Glossary on FIP:

Fielding Independent Pitching, a measure of all those things for which a pitcher is specifically responsible. The formula is (HR*13+(BB+HBP)*3-K*2)/IP, plus a league-specific factor (usually around 3.2) to round out the number to an equivalent ERA number. FIP helps you understand how well a pitcher pitched, regardless of how well his fielders fielded. FIP was invented by Tangotiger.

While I'm at it, here's xFIP:

Expected Fielding Independent Pitching. This is an experimental stat that adjusts FIP and "normalizes" the home run component. Research has shown that home runs allowed are pretty much a function of flyballs allowed and home park, so xFIP is based on the average number of home runs allowed per outfield fly. Theoretically, this should be a better predicter of a pitcher's future ERA.

Russ can explain these stats a whole lot better than I, but the idea is that a pitcher's ERA is affected by defense, and these stats try to eliminated that effect. FIP would be more of an 'expected' ERA.