Monday, September 14, 2009
What to make of pre-ranks?Posted by Derek Ambrosino at 2:01am
It’s hard not to be influenced by pre-ranks. A novice owner may simply defer to authority. An owner use a pre-ranking to confirm a preference for one player over another. And even the savviest of owners may be taken aback if there is a large chasm between their opinion of a player and his pre-ranking.
This week I want to dive into the volatility and accuracy of Yahoo pre-ranks and see if there’s anything we can learn relating to keeping or drafting highly pre-ranked starters, closers, and position players. In most of my keeper leagues, we don’t declare keepers until relatively soon before the season begins. That means pre-ranks are up already and may be a tool one uses when making decisions.
How reliable are those rankings? Are they more reliable for batters, starters, or relievers? Here, I’ve decided to take a snapshot of Yahoo’s top 100 players coming into the season and what the current top 100 actually looks like. This is hardly scientific, as it is only one season, which isn’t even complete yet. But, let’s see if there are any clear trends that emerge.
|Player Type||Pre-ranked top-100 (PRT100)||Actual top 100 (AT100)||PRT100, but not AT100,||not PRT100, but AT100||PRT100 vs. not PRT100 as % of AT100||Success rate|
For 2007 and 2008, I can’t access the pre-ranks, but here’s the final composition of the top 100 for each year:
|Player Type||Percentage of top 100|
|Player Type||Percentage of top 100|
Here are some trends that emerge from the data:
- The pre-ranks are not particularly accurate. Overall, only 51 of its projected top 100 actually finished in the top 100. Removing the top 25 (surest things) from the equation, would substantially drop the already underwhelming success rate of the pre-rank predictions. The highest pre-ranked pitcher to fail to rank in the top 100 for reasons independent of injury is Cole Hamels, who was ranked at 45. For batters, it’s Jimmy Rollins at 14. (Rollins could easily finish in the top 100 though—the surest bet is B.J. Upton, who was pre-ranked at 16).
- Although I don’t have the pre-rankings for 2007 and 2008, I feel confident presuming that relief pitchers are most drastically under-represented in pre-rank top 100s. In 2007 and 2008 there were a total of six non-closer relievers ranked in the top 100. This tidbit underscores positions taken by me and Marco Fujimoto regarding the value of elite non-closer relievers.
- The average composition of the top 100 over the past three seasons has been 63 percent batters, 25 percent starters, 12 percent relievers, an approximate ratio of 5:2:1.
- In 2009, the pre-rank was about 10 percent more accurate at predicting actual top 100 batters than it was predicting pitchers, though that may be entirely mitigated by the sample sizes.
At some point, the pre-ranks start to become nearly meaningless. Next week, I’ll delve into the 51-100 segment of the list, where presumably the bulk of the variation occurs, and explore whether the pre-ranks are a viable tool at all once decisions start to get a little more difficult.
Let me also add two quick notes before I close. First, I chose to remove players who didn’t perform at top-100 level because of injury, being that injury is a constant every year that is more or less random depending on the particular player. Two, if anybody has information about the year-to-year volatility of fantasy production for pitchers vs. batters, that would make a great companion resource to this piece.
Derek Ambrosino aspires to one day, like Dan Quisenberry, find a delivery in his flaw, you can send him questions, comments, or suggestions at digglahhh AT yahoo DOT com.