During spring training and now opening weekend, the White Sox have shown an increased aggressiveness in testing arms to home plate. On Friday, third base coach Joe McEwing waved home Alex Rios on a softly hit ball to left field, scoring him from first base. Earlier in the week in the first exhibition game against Houston, Alejandro de Aza hit a grounder to the left of Astros second baseman Jose Altuve. Dayan Viciedo was on second and he ran hard to third base. McEwing saw that Altuve dove for the ball on the outfield grass but could not corral it. McEwing never put up the stop sign and the Tank never slowed down, scoring easily without a throw.

Of course it hasn't all been sunshine as, for example, Brent Morel was easily thrown out at the plate on March 15 against the Inidans after a good relay from Ryan Spilborghs to Jason Kipnis and on to the waiting Carlos Santana.

We're obviously looking at a small sample. But what we appear to be seeing is an aggressive team baserunning approach where nothing is assumed until McEwing puts up a stop sign. And McEwing doesn't seem too inclined to put up the stop sign.

As Wavin' Wendell Kim can tell McEwing, there is certainly a line in fans' minds where aggression crosses over to recklessness. But this line probably isn't where it should be. Lulled by a game populated by conservative and/or inept tactics (sacrifice bunts, intentional walks and so on) and spurred on by an even more conservative and tactically inept media bent on fueling controversies, fans often view the game through the lens of loss aversion. While most of you aren't steeped in economics or decision theory, the concept of loss aversion is probably familiar to you: people have a tendency to strongly prefer avoiding losses to acquiring gains. Translated to baseball, they're going to disproportionately ding a third base coach for sending a runner who ends up getting thrown out - even if it was tactically the correct decision.

While there aren't a lot of studies out there on this topic, what is out there suggests that the fans' perception of third base coaches doesn't necessarily match up to reality. This one suggests that Wendell Kim wasn't bad and, instead, was the victim of crappy baserunners who, without him, were running into even more outs. Amusingly, the first comment on that study was someone saying that the study was nonsense because "we KNOW that Kim is awful" and, therefore, anything that doesn't confirm that KNOWledge must be wrong.

Another oft criticized coach was the Royals' Dave "The Windmill" Owens. And, again, the conventional wisdom was called into question once somebody actually did more analysis than "OMFG, WTF Owens!?!1?11!" after a runner was thrown out at the plate. [Less than a month after that analysis was published, Owens was fired when Ned Yost took over as manager.]

There are a few things going wrong with these perceptions. One of them is that a large number of baserunners thrown out isn't per se a bad thing. Another is that a high success rate (meaning percentage of runners safe at home) isn't necessarily a good thing. That's because we need the additional context of success rate in given situations.

Obviously, a third base coach is dealing with numerous variables - number of outs, runner, outfielder, where the ball was hit, score, who the next batter is, where the runner is when the outfielder reaches the ball, among many others - and not a lot of time in which to make a decision. And those variables are what makes granular analysis of decisions rather difficult. It's quite time-consuming to find and compile all of that data into a spreadsheet.

But there are some guideposts out there. We do know, on average, the run expectancy of given situations. I've lifted from the Owens study, which uses 2009 data, part of the decision process for a single with a runner on second:

So here is a chart of the initial run expectancy (RE), runs if the runner scores, if the runner stays at 2B, and if the runner is thrown out. Finally the break even success rate is given. In this scenario the runner that singles stays on 1B. Outs Starting RE Runs Safe at Home, 1xx RE 1x3 RE Thrown Out at Home RE Success Rate to Break Even 0 1.12 1.96 1.80 0.56 89% 1 0.70 1.56 1.22 0.23 74% 2 0.34 1.23 0.50 0.00 41% Let's walk through 0 outs for an example. The initial RE is 1.12 runs. If the runner stops at 3B the RE jumps to 1.80 runs. If the runner actually makes it home, [the team] only gains 0.16 runs on average. The 1.96 runs comes from the run scored counting as a run and the runner on 1B with no outs counting as 0.96. If the runner is thrown out at home, the RE drops to 0.56 or a loss of 1.25 runs if the runner had stayed at 3B. To get the success rate you total runs lost (1.25) divided by the total runs lost and gained (1.25+0.16) times 100% to get the success rate of 89%. The third base coach needs to make sure the runner is going to make [it about] 90% of the time to break even. The percentage drops to about 75% with 1 out. The success rate drops to 41% with two outs. It is much tougher for the run to score since an out (pop-up or ground out) won't score the runner. With 2 outs, it looks like even if there is a 50% of the runner being thrown out, the base coach should send the runner and they would come out ahead over the season.

So we can see a pretty big difference in the break even point from 0 outs to 2 outs. Of course, a third base coach should be well above those break even points because most of the time, given the game situation, the coach is going to be sending a runner in a situation where he has a higher level of confidence in the runner scoring (e.g., De Aza is on third base and Adam Lind caught the ball on the warning track - that's a score 100% of the time).

Third base coaches as a group appear to be overly conservative. They get it about right with 0 outs. But they're leaving runs on the table, particularly with 2 outs. And part of that conservatism is probably because they're cognizant that the reaction will be negative if a runner is thrown out at the plate, particularly if it ends an inning, and that negativity is going to be aimed squarely at the guy who sent the runner. [This is also known as blame avoidance, for you armchair psychologists.]

Another 2009 study illustrates this conservatism, with this analysis looking at sacrifice flies without 0 outs and using the Phillies as an example:

In 2009, there were 97 instances where this sort of situation occurred: no outs, runner on third, fly ball to the outfield. When the runner tried for home, he was safe 96.2 percent of the time (75-for-78). In fact, Perlozzo himself was perfect in 2009: 100 percent of the runners he sent in this situation (and in all sacrifice fly situations) reached home safely.

While I don't know for sure, Sam Perlozzo probably was lauded for this (my admittedly cursory internet search didn't find criticism of him). But, unless we believe Perlozzo is God, having a 100% success rate - not just in this situation but in all sacrifice fly situations - basically means he's only sending guys when he is just about 100% certain they'll score.

The breakeven point for the specific situation discussed - runner on third, 0 outs, flyball - is about 73%. That means the third base coach should be at least 73% sure that the runner will score if he's sent. Again, that doesn't mean that a third base coach's success rate should be 73% (the study draws that incorrect conclusion). But it does mean that, if a third base coach is making optimal decisions, his success rate will be above 73% but certainly below the 96.2% success rate observed in 2009.

Whether they're aware of it or not, third base coaches overestimate the ability of outfielders to throw runners out and/or overestimate the breakeven point. By how much is unclear. Obviously, this is an area ripe for further analysis, as illustrated by both the dearth of analysis of the topic, as well as some of the incorrect assumptions and conclusions drawn in what analysis is out there.

Getting back to McEwing,we're not going to know for at least a few months whether he's more aggressive than the average third base coach. But these studies suggest that it would be beneficial for the White Sox if McEwing quickly got the nickname Go Joe McEwing because the average third base coach appears to be overly conservative - and the fans may well be part of the reason why.

So, the next time a White Sox runner gets thrown out at the plate and you react by audibly asserting that McEwing has illicit relations with his mother or by writing a post on SSS hypothesizing how low McEwing's IQ must be to have sent the runner, pause and consider that you may not know what you're talking about. If runners aren't getting thrown out, McEwing isn't doing his job.