The Factor12 Rating

The Factor12 Rating (F12) is a measurement utilizing league average performance to compare the value of all MLB pitchers for a given season.

F12 consists of the following twelve statistics, incorporating every aspect of pitching….

Innings Pitched (IP); Strikeouts Minus Walks (SO-BB); Fielding Independent Pitching (FIP); Earned Run Average (ERA); Walks plus Hits per Innings Pitched (WHIP); Home Runs per 9 innings (HR/9); Walks per 9 innings (BB/9); Strikeouts per 9 innings (SO/9); Opponents Batting Average (OBA); Opponents On-Base Average (OOBA); Opponents Slugging Average (OSLG); Modified Base-Out Percentage (MBOP) includes wild pitches and balks. For 1876-1944, Rick Swanson’s Power Pitching (PP) replaces OSLG due to unavailability of accurate Total Bases Allowed data.

F12 produces a rating number using the percentage difference equation for the ten ratio categories. Each pitcher is ranked according to league average performance using 2.000 as the baseline. Categories have a maximum value of 4.000 and a minimum of 0.000.

The Innings Pitched (IP) and Strikeout Minus Walks (SO-BB) categories utilize a percentage change formula, which does not contain a fixed range.

A pitcher’s F12 is the sum of the percentage difference/change value of the twelve statistical categories. Pitchers recording zero innings pitched will receive a 0.000 F12 Rating. Elite pitchers will accumulate a 30.000+ seasonal rating.

Pitchers completing less than the average yearly innings (i.e. 65.75 in 2011) will have their F12 Rating weighed by the percentage of innings completed in relation to the league average (i.e. Sergio Romo 48 IP/65.75). This adjustment enables starting pitchers and relievers to be compared.

History of Factor12

(by Sven Jenkins, 4/4/2012)

With the release of the Factor12 Rating this week, I figured I’d put together a brief history of the project. The F12 story is full of unlikely scenerios that began in Poughkeepsie, NY in 1996.

The gist of the Factor12 Rating was born in both the lounge of Dutchess Community College and the Price Chopper picket line. Ideas were brainstormed at school, and numbers were crunched at work. Originally used as a fantasy baseball scoring system, FactorTwo (as it was called then) used a variation of the percentage change formula to compare each player with the league average to determine a fantasy score.

FactorTwo led to the creation of the original Picket Line Production Fantasy Baseball League, which has since been revived thanks to Yahoo. FactorTwo included every statistic found in USAToday‘s weekly printing of MLB totals. The league used Wins, Losses, Games Finished, etc…. many stats that have since been realized nearly useless by today’s sabermetric community.

Due to the excessive man power needed to enter all the data, the PLPFBL met its maker at season’s end. After the epic collapse of the league, the FactorTwo spreadsheets sat on a 3.5 inch floppy disk, inside a plastic bin for 16 years.

Josh Robbins unearthed the disks this winter and purchased an external disk drive on eBay to reclaim the files. What he found was a curiosity at first, but after I made the comment, “I wonder where all these players ranked”, the project was reborn.

Realizing that we might have the framework for a legitimate baseball metric in our hands, two months of hard work followed that conversation. Josh and I contemplated the value of a strikeout and the philosophy of FIP (Fielding Independent Pitching). I had nightmares about division by zero and Josh memorized league innings totals back to 1950. Eventually, we discovered the percentage difference formula and almost became real mathematicians by the end of the process. With the Cactus League season coming to an end, the Factor12 Rating was completed just in time for Opening Day 2012.

(Factor12 is the result of the collaborative effort of Josh Robbins and Sven Jenkins, with additional credit to each member of the 1996 Price Chopper picket line)