The 20-80 scale is a rating scale that scouts use when they are evaluating prospects, but there wasn't a scale that could be used when evaluating major league talent. That is, there wasn't until Mark Smith of FanGraphs decided to create one.
When someone says that a player is an [insert grade], what should we actually expect them to do statistically at the major-league level? Armed with some advanced statistics and z-scores, I went to find out.
To create the scale itself, statistics and z-scores were used and the data was gathered from 2010-2012. For batters a 20-80 scale was created for the following categories; hit tool, power tool, speed tool, and arm tool. Within those main categories there were a couple of subcategories. For the hit tool, batting average and BABIP were looked at.
Within the power tool Jose Bautista was the only player who managed an 80 ISO an HR/PA, which isn't terribly surprising.
For pitchers, velocity and control were the two categories that were looked at. As the other tools they also had a subcategory. There was not a starter or reliever who had velocity that rated as 80. Stephen Strasburg's 95 MPH fastball came in as a 70, and Daniel Bard's 97 MPH fastball rated as a 70 as well.
This tool is something that is extremely useful, and Mark did a tremendous job with the research. There are tons of other metrics that could be done, but this was a great start.