Defensive Estimating PDF Download

Much of the credit for helping the Red Sox win the World Series went to a more scientific approach to baseball statistics, dubbed "sabermetrics" by its greatest proponent, Bill James. But one aspect of the game has defied quantification: the number of runs individual fielders save. Traditional fielding statistics count errors and plays made, but not hits fielders 'should' have reached. Major League teams have recently addressed this gap using proprietary records of the location of every batted ball, but the underlying data has been kept secret and will never exist for the first century of modern major league baseball history. Now, in Wizardry, comes the long-awaited breakthrough, Defensive Runs (or Regression) Analysis (DRA), created by Michael A. Humphreys. Drawing on entirely public information available to any fan, and using clear concrete examples, Humphreys demonstrates how to apply classic statistical methods to estimate runs saved by fielders going back to 1893. Humphreys tests his results against other fielding measures, including published ratings based on proprietary batted ball location data, and explains their respective strengths and limitations. More than that, Humphreys introduces the first method for adjusting historical player ratings to take into account the expansion of baseball's talent pool due to population growth, integration, and international recruitment. From shortstop to left fielder, he presents and defends his list of the greatest fielders of all time with anecdote-rich essays. And he caps off this book with extensive on-line appendices, including downloadable files of single-season DRA ratings for every fielder since 1893. Sabermetrics changed baseball and introduced a generation of young people to the art of statistical inference. Now a seasoned analyst makes the case for the biggest changes in historical player valuations in decades, while opening up new approaches for further exploration.