Tuesday, December 22, 2009
The ‘optimistic’ Bill James projections
Posted by Derek Carty at 3:00am |
| Bill James has A-Rod down for 37 HRs while CHONE has him down for 34. Does that mean the James system is higher on A-Rod than CHONE? The answer may surprise you. (Icon/SMI) |
It's that time of year when projection systems are starting to be released. CHONE was released about a month ago, ZiPS is in the process of being released one team at a time, and Marcels will probably make an appearance sometime in the next few weeks. For hardcore fantasy baseball enthusiasts, it can be a lot of fun to go through the various systems and see how they are viewing players and how they stack up against each other. While I enjoy this time of year as much as anyone else, one of my biggest pet peeves is when people start talking about how optimistic the Bill James projection system is. Some examples of this sentiment:
Pending Pinstripes (Yankees blog):
I've always thought that the Bill James projections were wildly optimistic, but they're still interesting to look at.
The McCovey Chronicles (Giants blog) comments section:
Considering how crazy-optimistic Bill James projections usually are, that seems awfully pessimistic for Affeldt.
The Crawfish Boxes (Astros blog):
Surprisingly, James has an offensive prediction for Chris Johnson, and even more surprisingly, James is somewhat more optimistic about Johnson than most of us on this board (including me). Obviously, James' system believes that Johnson's minor league numbers indicate decent enough power to offset, at least in part, a paltry OBP. I have my doubts on that.
South Side Sox (White Sox blog):
James tends to have the most optimistic projections of any of the major forecasters, specifically for young players.
Driveline Mechanics:
The James projections often seem optimistic...
I think you get the idea.
Flawed logic
Inevitably, each year, the James system seems to be higher on the vast majority of players than are other systems such as CHONE, ZiPS, or Oliver. And inevitably, each year, baseball analysts see nothing wrong with making straight comparisons between systems. A couple weeks ago, I saw one article about Jake Fox that read:
For 2010, Bill James projects a whopping .284/.339/.546 line for Fox in limited playing time. That strikes me as wildly optimistic. CHONE’s forecast appears much more reasonable, with a projected .257/.316/.452 performance.
Other times, we'll see straight comparisons to previous years:
Bill James is super-optimistic - when I looked at the projections they came up with a few years ago, he had the majority of starters being better than average at every single position.
Still other times, sites will refer to the James projections while completely ignoring the context under which they were created:
James also projects Jose Reyes will return from injury to hit .285 with 57 stolen bases, 14 home runs, 67 RBI and 113 runs created.Or:
…man, i hope so… it looks to me like James essentially took Jose’s brief 36 games in 2009 and extended them out over 162 games, which is totally fine by me.
The projections here are extremely pleasing. I believe that they’re too optimistic, though, especially for the bullpen.
This isn't a shot at these articles or writers in the slightest, but I believe this line of reasoning—which is common across many sites and blogs—is a bit flawed, so today I'd like to help correct some of the common errors and misconceptions that many seem to have about projections.
Relativity and context
The most important concept I'd like to stress is that of relativity. The kinds of articles I just mentioned operate under the assumption that the James projection for a player should be looked at relative to another system's projection for him or relative to last year. This is incorrect, though. What we should be doing is examining the James projection for a player relative to all of the other players the James system projects.
As I've stressed many times before, context is of the utmost importance when it comes to almost anything fantasy baseball related. In this case, most people ignore the run environment that the James projection system assumes. To illustrate my point, I'll use a very extreme example. Let's say that we transport Albert Pujols and his 44 HR projection into a league where it is common for the worst players to hit 80 HRs per year and the best to top 200 HRs. While Pujols and his 44 HRs look terrific in our reality, in this new one it looks kind of pathetic. That's context.
"What does this have to do with the James projections, though," you ask? Well, while the James projections don't assume a run environment where people are routinely hitting 200 HRs, it usually does assume that hitters perform a little bit better, on the whole (when compared to previous seasons or other projection systems). So if everyone is being projected to hit a few extra HRs, it does not necessarily make Alex Rodriguez's 37 HR projection any more optimistic than CHONE's 34 HR projection.
After all, when we're drafting players in fantasy leagues, it doesn't matter if the first pick has 200 HRs and the second pick has 190 or if the first pick has 40 and the second has 38. We don't care about the actual numbers; we care about the relative rankings. It doesn't matter if James has Albert Pujols at 44 HRs and CHONE only has him at 39. If James is inflating numbers across the board, Pujols will still be considered the No. 1 pick and everyone else will fall in line behind him, regardless of the system used or whether or not its numbers are inflated relative to other systems—we just can't mix-and-match.
Comparing systems
So how can we compare systems if we can't do it directly? Ideally, we'd find the league average for all systems for all of our relevant stats (or even more ideally, the average for all players that will be drafted in a particular fantasy league, though that obviously works better in theory than in practice) and create a set of conversion factors so direct comparisons can be made between systems.
I didn't buy the Bill James Handbook or the projections this year, so I don't know what its league average is (and thus am not 100% certain that the James system is actually inflating stats this year, but they have been inflated in the past and anecdotally seem to be this year). If anyone wants to share what the league average is for James (or other systems that require payment), I'd be happy to whip up some quick conversion factors and post them for everyone to make use of.
Outliers
"But what about players whom the James system is extremely high on? Should they be disregarded?" Of course not. Like any other system, James will like certain players more than those other systems. They're just a little tougher to pick out without applying the conversion factors since we have to guess at how much we should discount their stats. One guy who might fit this criteria this year, though, is Mark Reynolds. James has him down for 40 HRs while CHONE is at just 30. Marcels will likely be closer to 30 as well when it comes out. That's a big difference, even considering inflation. We just need to remember that all systems will favor certain players and show a distribution of players they like (relative to other systems), dislike, and are neutral on.
Fan Projections
One last point is that the fan projections FanGraphs is running will likely be sitting in the same boat with the James projections. I'd guess that fans will be more apt to project players they like, which means league average will probably be a bit higher for these projections as well. Just something to keep in mind.
Concluding thoughts
Hopefully this has cleared up some confusion regarding projections, specifically regarding the Bill James system. If you have any questions, feel free to e-mail me or post in the comments.
Derek Carty, 23, has also been published by NBC's Rotoworld, Sports Illustrated, FOX Sports, and USA Today. This season, he'll be contributing to FanDuel and will be linking to all of his work at DerekCarty.com. In his three years competing in expert leagues, he has won 2 titles with 4 top three finishes, including a LABR NL title in 2009, making him the youngest person to ever win a major expert league title. Derek is a proud graduate of the MLB Scouting Bureau's Scout Development Program and is a firm believer in the importance of combining stats and scouting. He welcomes questions via e-mail, Facebook, or Twitter.
Hah, I remember writing that. I think I was more referring to young players. Austin Jackson’s projection was a little outlandish, giving him a .341 wOBA and a .371 BABIP—those two things are very unlikely to happen.