not being a dick but i don't think that has an effect. i've never looked into it too too deeply. i'd have to see examples of what counts as what, explained to me in person by the dudes doing it, to realize the differences in some plays. i was a slave to defensive metrics for a good bit and have backed off considerably.
as I understand it, the numbers determines (using film study and computer comparisons) how many more or fewer successful plays a defensive player will make than league average. For instance, if a shortstop makes a play that only 24% of shortstops make, he will get .76 of a point (1 full point minus .24). If a shortstop BLOWS a play that 82% of shortstops make, then you subtract .82 of a point. And at the end, you add it all up and get a plus/minus. (Joe Posnanski, Sports Illustrated)
fun little snippet from DRS | FanGraphs Sabermetrics Library
that ^^^ is really tricky territory. which is why metrics are eh/still growing.
