Player rankings can seem mysterious at times. Auction values, even more so. How do your favorite fantasy baseball sites come up with these things? From ESPN to Yahoo to CBS, it's tempting to think they're totally arbitrary, just players and numbers thrown on a board at the author's whim (some of them certainly are… I won’t name names, but yikes). As it turns out, there are actually several player valuation systems that are commonly used to come up with player rank - these calculations, combined with your projection system of choice, allow you to directly calculate player values and rankings!

This is the best way to value players. It forces you to decide what you realistically project a player for. You want to move a player up your board? Fine. But you should do it by adjusting a projection, not by arbitrarily deciding A is better than B because reasons. Decide how realistic you really think it is that Giancarlo Stanton is going to play 162 games and hit 50 yaks (you think he is? ok.gif), and adjust accordingly. And when you find yourself playing in your cousin’s 10x10 league with all sorts of wacky categories, you pretty much have to rely on the projections to tell you what to do, since the typical 5x5 wisdom is totally out the window.

I throw around the terms "z-score", "SGP", and "Points" fairly liberally here on the Harper Wallbanger blog. Fantasy baseball loves its jargon. All of these terms describe systems used to assign player values when generating rankings or auction prices. But if you're not a hardcore spreadsheet wizard, you might be wondering what the differences actually are in how these are calculated. Especially given that the Big Board allows you to choose any of the three systems, it's time to bring some clarity to this situation!

A technical note before we start: the "BIGz" score used in the Big Board was originally just a z-score, hence the "z". These days, it's a catch-all term used for any of the $ values generated by the sheet, no matter the valuation system used.

There are four basic steps to the creation of BIGz $ values for players from raw projections that I'll step through and explain:

(1) Initial calculations (different for each system)

(2) Modifications (h/p split, aging, bonus PT)

(3) Replacement levels (positional adjustments)

(4) Dollar conversion



1) Initial Calculations

z-Scores

z-Score: a statistical measurement of a score's relationship to the mean in a group of scores. A z-score can be positive or negative, indicating whether it is above or below the mean and by how many standard deviations. A z-score of 0 means the score is the same as the mean, while a z-score of 1 means the score is exactly 1 standard deviation above the mean.

z-Scores are probably the most popular system for creating player rankings and dollar values, thanks to their relative simplicity. I originally encountered them in the form of ‘FVARz’ (Fantasy Value Above Replacement z-scores) as popularized by Zach Sanders (formerly) of Fangraphs. The first step of creating player values in this system is to calculate and sum the z-scores for every player. To do that, you need to know the average and standard deviation of every given stat used in your league. I use the past three years (2017-2019) of collected stat lines from all qualified players to do this. Here are some of the values currently used in the Big Board: