My name is Rob Elzer. I am a 19 year old college sophomore at the University of Pittsburgh, majoring in statistics. A few years ago, I developed my own advanced baseball stat, the Rob Elzer Value Metric(REV). In this, my first post, I will explain what REV is, how to interpret it, and tell you what I will be writing about in this blog.
REV attempts to compile everything a player can do into one metric. It is expressed on a winning percentage scale, which means an average REV is .500. Each player is numerically rated on the attributes I believe are most important to a player’s success. Position players and pitchers are rated separately because they do very different things. The attributes I use for position players are Contact, Power, Plate Discipline, Speed, Base Running, Fielding, Durability, and context dependent clutch ability. For pitchers, the attributes are Strikeout rating, Walk rating, Home Run Rating, Stamina, Durability, and context dependent clutch ability.
To consistently apply ratings for each of these attributes, I created scales. In these scales there is a rating that corresponds with every possible statistic I use for each attribute. Here is the attribute line for the player with the highest REV in 2017, Mookie Betts:
Earlier in the post, I stated that REV is expressed on a winning percentage scale. As you can see, Mookie Betts had a .934 REV last year. This means that if there were a team full of Mookie Betts, that team would have a .934 winning percentage. I believe that by using that interpretation, REV is very simple to understand. If you understand what a winning percentage is, you can comprehend how good of a player Mookie Betts is. This interpretation also makes it easy to establish some guidelines:
- .700 and above are elite players
- .650 is a great player
- .600 is a well above average player
- .550 is an above average player
- .500 REV is an average player
- .450 is a below average player
- .400 is a well below average player
- .350 and below are players who probably should not be in the MLB
Because starting pitchers and relief pitchers are rated together, they follow slightly different guidelines. An average starting pitcher generally has a REV of about .570, while an average relief pitcher usually has a .440 REV. You can adjust your interpretation accordingly when I discuss specific pitchers in future posts, depending on whether they are a starter or a reliever.
Using the winning percentage interpretation of REV, I have developed a record projection system. I have done this for two years now and it has yielded similar results to some of the top projection systems like Fangraphs, FiveThirtyEight, and Baseball Prospectus.
Here is a list of things to keep in mind about REV in future posts:
- Pre-Season REV includes position players who accumulated at least 250 plate appearances over the past three seasons and pitchers who have accumulated at least 65 innings pitched.
- Both Major League and Minor League stats are used for players with less than 750 plate appearances and pitchers with less than 150 innings. The scales are adjusted for minor league stats.
- In-Season REV includes every position player and pitcher who are on a team’s 40-man roster.
- In-Season REV is updated everyday.
- While REV and Wins Above Replacement(WAR) are both value based stats, REV is a projection which tells you how the player is expected to perform the rest of the season.
In this blog, I will be analyzing happenings in baseball using REV. With the MLB postseason drawing to a close, it may seem like a weird time to start a baseball blog, but I have enough to write about everyday. During this offseason, you can expect free agent analysis, team analysis, the top 100 players and pitchers in pre-season REV with analysis on each player, and much more. By using REV, I will provide you with unique analysis that you will not find anywhere else. I will be able to identify undervalued players and I will use percentile rankings for attributes to explain the strengths and weaknesses of players. Feel free to comment if you have any questions or if you have input to provide.
Follow REV on twitter @REVmetric to check out my postseason game predictions and for a lot more cool analysis. #JoinTheREVolution