Thursday, February 18, 2010

Replacement Value and Scarcity in Fantasy Baseball

Like most complex topics, I think most people try to oversimplify the idea of 'replacement value'. That results in projections and draft strategies that end up taking it into account incorrectly. To avoid the pitfalls associated with the concept, you should keep one thing in mind all the time: when I'm valuing or choosing a player, what is the relative value of the players I may end up with instead? During the season, there's a simple way to approach this. If I need to pick up a player at any given position, how good is the best player available on the waiver wire at that position? That's the replacement value to use for players at that position (for example, when I've evaluating potential trades). On the other hand, things are more complex when you're looking at replacement value as part of your draft preparation. You don't care about the quality of players who will end up on the waiver wire post-draft, because those are not that players you're going to end up with if you don't draft 'Player A' at a position. Instead, you should be thinking about position scarcity. What players are you likely to end up with at the same position later on in the draft if you pass up the player you're evaluating now? If you were going to attempt to quantify it (which would be a very difficult task), the scarcity or replacement value you cared about would be something like the average quality of remaining draft-worthy players at that position, weighted by the likelihood of each player ending up on your team. Obviously, most of you are NOT going to try to measure that, but you can instead group players by tiers at each position. That way instead of looking at the worst third baseman and the worst first baseman and assuming the position have equal 'replacement value', you'll know that after the 4th round or so of most draft, there's enough scarcity of quality third basemen that you're likely to end up with someone very mediocre, while there are still plenty of strong first basemen who are likely to be available over the next few rounds.

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