In my last post, I looked at how often various categories are used in fantasy leagues and which core stats are used to predict them. Today, I am using those stats to predict Runs and RBIs
Run and RBI generation, except with home runs, require other players to either be on base or drive the player home. I ran many regressions and adjusted formulas using the inputs from my last article. I used some stats that weren’t listed (ISO, SLG, Spd). After many attempts, I came up with the following simple equation for projecting a player’s Run and RBI production:
Runs or RBI’s/PA = (AVG * 0.330 + BB% * 0.187 + HR% * 0.560)(yearly constant)
r-squared of 0.75 for 2011
yearly constant = 1 for 2012 for now. It will change depending if the run scoring environment changes.
The preceding equation gets the rate of the Runs and RBI per PA. Knowing some of the player’s talent, Walks, AVG and HRs, an idea of how many Runs and RBIs they generate can be determined.
Using Ryan Howard as an example, he should have accumulated 86 Runs and 86 RBIs in 2011 (actual values: 81 runs, 116 RBIs in 644 PAs). These number are a little off, but there are a couple adjustments that need to be made first.
The position in a team’s batting order matters. The players at the top of the order will have less RBI opportunities since they start off the game with no one on base and have the bottom of the lineup hitting before them. The 3 to 5 spots will be hitting with high OBP before them and get more RBI opportunities. Here are the RBI and Runs multipliers for each batting order position:
The top two spots allow a player to generate more Runs, while the 3-5 spots are the RBI positions. It is pretty common sense, but the values are the key.
Using Ryan Howard as the example, he hit only in the 4th spot all last year. Using the multipliers, he would get his values adjusted to 82 Runs and 98 RBIs
Besides the position in the lineup, the quality of the team’s other hitters matter. Having better hitters around you will lead to more run scoring opportunites. Using the team’s R/G, a Multiplier for Runs and RBI can be determined:
Multiplier for Runs and RBIs = Team Runs per Game/(4.28 R/G)
One problem I have seen is that some teams have a cluster of good hitters (Cards with Sir Albert and Holliday) and other have them spread out through the lineup (the Rays). The players on teams that have clustered talent will have more of the RBI and Runs opportunities among those clustered players. I am wanting to keep it simple and will not adjust for clustering for now.
Using the team adjustment for the Phillies (1.026), Ryan Howard ends up with 84 Runs and 101 RBIs. The number of runs are close, but the RBI’s are down from the actual values. They do give an idea of what to expect from him knowing just a few stats.
Well, that is it for today. In the next part, I will be looking at predicting PA and SB. Let me know if you have any questions or suggestions.
Jeff, one of the authors of the fantasy baseball guide,The Process, writes for RotoGraphs, The Hardball Times, Rotowire, Baseball America, and BaseballHQ. He has been nominated for two SABR Analytics Research Award for Contemporary Analysis and won it in 2013 in tandem with Bill Petti. He has won three FSWA Awards including on for his MASH series. In his first two seasons in Tout Wars, he's won the H2H league and mixed auction league. Follow him on Twitter @jeffwzimmerman.