- FanGraphs Sabermetrics Library - http://www.fangraphs.com/library -

Statistic Percentile Charts

How awesome is this chart? It’s simple, easy to understand, and imparts a swath of information all at once. I had no idea what league-average Isolate Power (ISO) was until now, but bam, there it is. This, my friends, is a thing of beauty. Until I saw this chart, I had no idea I needed all this information, but now that I’ve seen it, I want more.

I suppose I shouldn’t be surprised: this work of genius was created by Lee Panas, the writer at Tiger Tales and the author of “Beyond Batting Average”, a concise, well written book geared toward introducing everyday baseball fans to sabermetric statistics and analysis. It’s a great book and I recommend it thoroughly (although in the spirit of full disclosure, I must admit that I have a soft spot for Lee: not only am I a fellow saber-ed nut, but like Lee, I’m forced to root for my favorite ball team from afar, stuck in the wintery hellscapes of New England).

But I’m not writing this article as a book review (you can find those elsewhere); I’m writing because of that beautiful graphic up above. One of the complaints I hear most frequently from saber-newbies is that while they want to use these new statistics, they have no idea if the numbers they’re seeing are good or bad. Is a .320 wOBA good? Exactly how bad is a -5 UZR? I know it’s bad, but is it only mildly bad or tear-your-eyes-out bad? And what, pray tell, does a 4.00 tERA mean? It’s one thing to understand the theory behind the statistic, but sometimes understanding its scale can be just as challenging.

And so, I’ve taken Lee’s lead and included similar charts on each of the statistic pages here in the Library. The league-average rates are all accurate, and I’ve estimated percentiles based on the scores of all batters with more than 400 PA and pitchers with more than 90 IP. These percentiles may not be 100% accurate in all instances, but they are close enough to work as estimates in order to provide context.

Thanks again to Lee for the inspiration. If you like the charts, go check out some of his work.