Edgy DC wrote: If defensive metrics aren't winning your confidence regarding which guys are getting to balls that might elude other guys, they should be able to tell by now, with some accuracy, how effective an outfielder's arm is --- not only regarding the guys you nail but the guys you freeze because they'd never run on you. Jay Bruce, for instance, had eight assists, an unimpressive number. Is he chilling the opposition from taking the extra base or failing to nail them when they do? The truth is out there. Problems of sample size abound of course. How many legitimate first to third decisions are there in which the ball is hit to RF? How much of it's because of third base coach? (A real aggressively bad coach could cause a lot of his runners thrown out, bonus to outfielders in his division) You have to break it down by outs too, since a runner is less likely to go (and more likely to have a head start and make it easily) with two outs. But surely you should look at defensive numbers, including the arm stuff. It's better than randomly guessing based on a handful of games you've seen, or errors, or genie, or however they do this. ARM (outfield arm runs): Outfielder�s get credit (plus or minus) depending on what the runners do on a hit or a fly ball out. A runner can stay put, advance, or get thrown out. A fielder will get credit not only if he throws out more than his share of runners, but also if he keeps more than his share of runners from advancing extra bases. Bruce had a -1.7 ARM last year, and has a total of 5.2 over his career. Duda, had a -5.7 last year and -9.2 overall. I'm not sure exactly how the stat is calculated but it seems Bruce is fairly average. There were 250 balls in his zone last year (120 for Duda) so 1.7 might be a percentage? perhaps he allowed an extra base or missed an out compared to the mean on ~5 balls over the course of the year. (edit, clearly it says it's the amount of runs. so -1.7 is particually nothing. )