Matt Meyers of ESPN.com discussing new MLB technology at the Sloan conference:
This will allow us to track every player movement. So, for example, when a fly ball is hit, we can see how far the outfielder ran to catch it, his direct route and his route efficiency, which is his direct route relative to his overall route. In other words, we can now prove which fielders take good routes to batted balls.
Fielding stats have continuously improved over the last decade. The idea of looking just at errors, fielding percentage and spectacular plays continues to drift further and further into the past each year. It has taken a long time, but people are finally coming around to the idea that these original stats are deeply flawed.
Take errors as an example. Errors are only given when a player actually makes a physical error with the ball, either failing to field it, or making a bad throw. If the guy playing shortstop doesn’t have a lot of range he won’t get to as many balls as someone who has better range. So someone who gets to way more balls than someone else has many more chances for errors.
That is where people will indicate that fielding percentage comes into play because it’s based on the number of errors a player makes vs. the number of chances he has. But again, the number of chances is only indicative of the number of balls the player actually gets his hand on vs. the amount of balls actually hit in his direction. A player with a .950 fielding percentage sounds a lot better than a guy with a .900 fielding percentage. Until someone finds out that the guy with the lower percentage accumulated 100 more assists (read: outs) than the first guy.
Even that logic is slightly flawed because there are so many factors from one team to another that play into the number of balls that are hit to a particular position on the field. That is why advances like movement tracking are so important. The ability to track what kind of route an outfielder takes, or how much quicker an infielder is at getting to balls will make a huge difference in evaluating who truly is a good fielder. If someone makes a lot of spectacular plays it might just be because they are a step slow and they make routine plays to the average fielder look hard. Those are the kinds of arguments that need to be solved.