Details on SABR Defensive Index and new Rawlings Gold Glove Awards selection process
Here are some more details about the new selection process for the Rawlings Gold Glove Award and Rawlings Platinum Glove Award, presented by SABR:
Why is Rawlings modifying its criteria for the Rawlings Gold Glove Award®?
Rawlings has a rich heritage dating back to 1887, which is an integral part of its identity, but it's also a progressive brand that stands for innovation. In much the same way it utilizes new technology to create high-performance products, Rawlings wanted to ensure that baseball's ultimate defensive award made best use of the information available. While managers' and coaches' votes are still the core criteria of the Rawlings Gold Glove Award, Rawlings acknowledges there are new ways to measure a player's defensive performance. Each year the metrics improve and become more accepted. We felt it was the right time to begin incorporating these measures into the iconic Award.
Why did Rawlings choose to collaborate with SABR on this initiative?
SABR is a respected leader in the baseball industry, with a special expertise in baseball data and analysis. As we sought out the "experts" in this field, it became clear that SABR was the ideal choice. As a non-profit, independent third party, SABR has no commercial interest in defensive measurement. This combination of objectivity and expertise was important to Rawlings.
How was the SABR Defensive Index (SDI) developed?
SABR formed the SABR Defensive Committee, led by SABR President Vince Gennaro. From its 6,000 members, SABR identified and appointed recognized experts in fielding data and analytics, some of which have put two or more decades of effort into measuring defensive performance. This group met throughout the spring and summer to evaluate the historical and current body of work on fielding measurement. The committee developed a framework and criteria to evaluate existing metrics and ultimately aggregated the leading metrics in a balanced way to create the SDI — a bottom-line measure of an individual player's defensive performance.
What fielding metrics make up the SDI?
The SDI is built from two types of defensive metrics — those that come from batted ball location-based data, and those which originate from the play-by-play records of games. We gave more weight (70%) to the batted ball location-based metrics, which evaluate the degree to which a fielder makes plays in specific zones on the diamond. The player's performance is measured in comparison to his peers. The play-by-play based metrics (30% of the SDI) are important in that they approach defensive measurement from an alternative vantage point — a more generalized approach that estimates the number of batted balls hit into a fielder's area.
Within the batted ball location-based category, we've included 3 measures — Defensive Runs Saved (DRS) from John Dewan's company, Baseball Info Solutions; Ultimate Zone Rating (UZR), authored by noted sabermetrician Mitchel Lichtman; and Runs Effectively Defended (RED) from Chris Dial. The play-by-play based metrics include two measures: Defensive Regression Analysis (DRA) from Michael Humphreys and Total Zone Rating (TZ).
What are some of the defensive elements that are measured within the SDI's components?
Fielding metrics included in the SDI capture a fielder's range, his throwing arm, his sure-handedness, his ability to turn double-plays (for SS and 2B), his ability to convert bunts into outs (primarily P, C, 3B, and 1B), scoops of throws in the dirt (1B), as well as the number of "excellent" and "poor" fielding plays. In addition, for outfielders, his ability to prevent runners from taking an extra base is also rated. For catchers, blocking balls in the dirt and stolen bases/caught stealing are also included in their ratings. Finally, for pitchers, we include his ability to control the running game by holding runners on base, in addition to many of the above criteria. (Pitch framing by catchers is not currently included in the defensive metrics that comprise the SDI.)
How will you blend the SDI with the managers' and coaches' votes?
The committee has created a simple way to convert the SDI—which is expressed in the number of runs a fielder "saves" his team—into 30 "votes" for each Rawlings Gold Glove Award awarded.
What percent of the overall RGGA criteria will the SDI represent?
The 30 votes originating from the SDI will be added to the votes we typically receive from the managers and coaches. Each manager and up to six (6) coaches on the major-league staff is allowed to vote for the Rawlings Gold Glove Award. NOTE: managers and coaches cannot vote for their own players. Based on the number of votes typically submitted from managers and coaches, the SDI will represent approximately 25% of the Rawlings Gold Glove Award criteria, depending on the number of votes received from the managers and coaches.
Is the SDI set in stone or will it change over time?
We foresee the SDI evolving over time to incorporate new developments in defensive measurement. Each year the SABR Defensive Committee will evaluate the SDI formula and consider new developments, including technological advances in the way fielding performance is measured. When new metrics become available, they will be evaluated based on their history, track record, credibility, and overall acceptance by both the statistical analysis community and baseball industry. If a new measure is deemed to add value to the current mix of metrics, it will be considered for inclusion, as either and additional component of the SDI, or a replacement for an existing component of the SDI. Our goal is to remain "current" with the state of fielding measurement, by utilizing the best metrics available.
Will the final season SDI or an on-going tally of the SDI be published?
The SDI will be included on the managers' and coaches' ballot that is distributed to all MLB teams in September. The final SDI for the 2013 season is now available to the public on SABR.org. We are still determining our plans regarding publishing the SDI on an on-going basis, during the 2014 season.
Will the SDI alter the way the Rawlings Platinum Glove Award winners are chosen?
Yes, the SDI will be incorporated into the Rawlings Platinum Glove Award criteria. The specifics are still being finalized and will be announced sometime in September.
This page was last updated August 18, 2013 at 8:00 am MST.