Fantasy owners (and baseball fans in general for that matter) make a lot decisions and engage in a host of arguments based on different sized samples of data. The first thing that someone disagreeing with an assertion will generally look at is the sample size. If you tout an unknown commodity after a hot week, you’re likely to get hammered for putting far too much stock into a 7-day period. Sometimes when we’re on the side that wants to be right, we’ll ignore obvious sample size issues in hopes of not being called out.
What is a big enough sample size? Honestly, that depends on what you’re asserting or trying to prove. If you look back at a .417/.489/.590 week of a player you chose over the .231/.300/.378 player for your head-to-head league match, then you can pound your chest a little bit because you clearly made the right decision. But if the latter player is clearly the better player and you let that week make you chose player A again then you start getting yourself into trouble.
Does a month offer enough data to start making judgments on players? Again, it’s going to depend at what you’re hoping to accomplish. At the beginning of the seasons, fantasy team owners across the world are hypersensitive to the highs and lows that their players (and even those not on their team) are going through. Entering May 1st, Emil Brown had 25 RBIs. He has 49 through Wednesday. Josh Willingham was hitting .341, but he has .167 since (missed all of May) to leave him at .260 on the season.
Most are familiar with the awful start of C.C. Sabathia, but it bears mentioning that he was 1-4 with a 7.88 ERA. After a complete game shutout of the Cardinals tonight, he is 10-8 with a 3.30 ERA. How many watched as the owner of Sabathia in their league dealt him for a quarter of his true value because it wasn’t just a bad start or two, but rather a month? Furthermore, how many watch Mark Hendrickson get picked up because of a 4-1 start with a 3.68 ERA for the Marlins? You start looking for reasons, however flimsy, to believe these things to be true. For someone like Hendrickson, it was the previous track record of Florida arms and the home stadium that all of sudden made him worthwhile. Sabathia was out of shape and his workload had caught up to him.
If a player has an established track record (of success or failure), then you shouldn’t begin to take numbers seriously until June 1st rolls around if they are going against that previously established record. Even at that point, you should be cautious of making hasty moves that could end up hurting you in the long run. Remember that on June 1st, there are still FOUR months in a fantasy baseball season. I’m not suggesting you have to stand pat until two months or more into the season, rather that it can be foolish that make moves because of numbers posted in the first 2-2 1/2 months into the season if they are inexplicably against years of unlike data. I grant that there are variables to this line of thinking that can come into play. Injuries, age, team situation (lineup/ballpark/playing time) are primary amongst these factors.
I have spent the last 500+ words telling you which time periods aren’t long enough to make, so what time period of statistics do I find suitable enough to make judgments off of for players who performing against career norms? I think a year’s worth of data is pretty solid. Meaning if a guy has a great 1st half, how is he looking against his peers when it is combined with his previous season’s second half? Believe it or not, a half season of data—no matter how good or bad—can be a fluke especially when it’s complete contrary to a player’s history that spans much more than a half season.
I’m going to post some of the 365-day Leaderboards so we can get a better idea of who has been performing the best over the past “season” worth of games. Plenty of this year’s top performers will be found within these lists, but others not currently atop the league leaders for 2008 will be scattered across these lists as well. This exercise isn’t meant to be a predictive measure so much as it is a better look who has been performing the best for a more sustained period of time than just the nearly four months of the 2008 season.
This set of lists covers the Top 25 across the main roto categories of home runs, runs batted in, stolen bases and runs scored. I took OPS instead of batting average because I (as many do) find it a better measure of a player’s value. I realize average or even on-base percentage are used in fantasy scoring, but went with the OPS anyway.
Again, I’m not looking at these to be predictive of the final two months of the season, instead just another set of data to chew on when judging talent. Most of the names found within the above listings have been getting it done for a full season’s worth of plate appearances and it wouldn’t be a horrible idea to rely on them to get it done for you during the final two months of the season.
I leave for Philadelphia tomorrow and I’ll be gone until Sunday evening. While I hope to have some stuff up during that time period, I’m unsure if I’ll have time for much of anything. When I get back, I’ll most assuredly report on my trip to Citizen’s Bank Ballpark as the Phillies play host to the Atlanta Braves. I think we’re down for at least Saturday’s matchup which features Cole Hamels against Jo-Jo Reyes. We might go to the Kyle Kendrick-Jair Jurrjens showdown on Friday evening as well, but that is TBD at this point.
Baseball By Paul 