He Got Skills

Last time I left us some questions. The first, and most fundamental question is; just what is a skill? We think we can recognize skills in ballplayers (and people) and sometimes we are right. In baseball though, with its panoply of statistics, we can be easily confused. A statistic is not a skill. The two can sometimes be related, but there are stats that should not be confused with a skill, especially some particular stats. Many of the so-called sabremetric or new baseball stats are more closely related to actual baseball skills, because incorporated in them is the notion of skill we are looking for.

Quite simply, a skill is an ability to complete a task, and complete it the same way in a highly predictable fashion, due to the fact that the person who possesses it has the right set of characteristics, mental and/or physical that allow for this. It should be also noted that a skill is an ability to complete a task repeatedly in circumstances that are fair to all of the many different possible outcomes of the task, and do it at at level beyond that which you would expect beyond random chance. So, for instance, it is not a skill to be able to flip a coin for a head and then a tail; this you would expect from random chance. It is not even a skill to flip a coin six, seven or eight times in a row for a head. This too could be just random chance, or it could represent a loaded coin (not fair to the two outcomes that are possible). Beyond this, at ten or twelve times in a row, you would have to expect that either the coin was loaded, or the person flipping it had some sort of skill to complete the task repeatedly, because beyond 8 or 10 or 12 flips in a row all heads (assuming no cheating), it is highly statistically unlikely that it is just chance determining the outcome.

I won't go in to the math here, but this would qualify as a skill, if the coin flipper could do this with regularity (always able to flip 8, 10 or more heads in a row, most of the times he was asked to do this task). In a fair environment, being able repeatedly to complete a task at a predictable level of ability beyond the level of probability of success that can be explained by random chance, qualifies as a skill.

OK then, with this definition of skill in hand, let's venture out into the world of ballplayers. There are a shocking array of statistics about baseball players all vying for your attention. Which ones should we pay attention to? Which ones should we pay the most attention to? Which ones are pretty much useless and should be ignored. This is where our new idea of a "skill" comes in. One thing I neglected to mention above about skills is that in order to be useful to us in evaluating baseball players, these skills must be measurable in some way. The simplest form of measurement is counting ("how many times did he do "X"?); the next simplest is rate measurement ("how many times did he do "X" for every opportunity, or for every time "Y" happened)?

Counting is easy, but unfair, as it credits those that have more opportunities than those who have less opportunities. Rate measurement is more fair, and levels the playing field, but in a game whose goal is not to perform at a certain rate, but to simply outperform your opponent's runs scored, we need to look for those players who actually perform at a high rate over many many opportunities (after all, a player who is injured or sick or suspended for bad behaviour for 5 days of the week, but performs at a high rate in some skill, is not, at the end of the week, worth as much to his team as the player who performs at a somewhat lower rate, but never misses an inning).

These are the two basic forms that most baseball statistics take: counting statistics, and rate statistics. Depending on context, each kind is important. But how do we know which statistics are most closely related to skills? In general, rate statistics are easier to evaluate as valid measurements of skills, because they remove the unfair advantageous influence that increased opportunity can introduce to counting statistics. Without going into the math though, it is very important when using rate stats as a means of determining skill to ensure that the number of opportunities used to measure the rate (the "Y" above) is sufficiently high to guarantee that you aren't just observing random chance or luck at work. Remember the coin flip. Two or three heads in a row is not anything unusual. However, 11 or 12 heads out of 12 flips is statistically significant, and is very highly unlikely to be due to just random chance or luck.

With this in mind, what we are looking for are statistics that reflect skills, that is, those statistics that, for a given player, do not vary dramatically from year to year (the player can repeatedly complete a task in a consistent fashion). Of course players get injured, and often play injured, and over time a player's skills can improve as he matures; and, as he ages, decline, but these two factors can be accounted for accurately when one is using a good statistic, one that actually measures a skill. I can't stress this enough: the best statistics to use to evaluate a player's skills are those that do not vary considerably from year to year, or those that show a predictable increase as the player grows and gets more experience, and then decline as he ages. These statistics are the ones that are the most reflective of a player's skills, because, we are safe to assume, the skill of a player is fairly constant for several years, so well thought-out and defined statistics should reflect this, and remain fairly constant, allowing us to compare players in a fair manner.

The flip-side of this of course is that we should be suspicious of statistics that swing widely in value for a given player from season to season, as these fluctuations are likely to reflect the influence of factors other than a player's skills. These highly variable stats could be showing the effect luck has on the outcome of his performance, or the influence of the skills of the other players on the team he plays on. These stats are of limited use to us in evaluating players and their skills and contribution to winning (and therefore each's objective value as a player). Of course it's always important to remember that we are looking for skills and stats that are related to the scoring (or prevention of scoring) of runs, as runs are what contributes to winning. It's great if a pitcher can consistently throw the ball at 102 mph (and therefore has this as a skill), but only if this can be shown somehow to contribute to winning ball games.

NEXT TIME: Which stats are good ones and which common stats are poor ones if our aim is to evaluate a player's skills and contribution to winning ball games? Remember, we are going to stick to the player's we can vote for on the All-Star ballot, so we won't look at pitchers stats ... well ... OK maybe this one time. Your homework is to answer this: which stat do you think better represents a pitcher's skills, ERA (Earned Run Average) or K/9 (Strikeouts per nine innings pitched)? For batters which is a better measure of a skill over two or three seasons; a player's RBIs (Runs Batted In), his AVG (batting average) or his K/PA (strikeouts per plate appearance). I'll give you a hint ... go look up the numbers for some of your favourite players and see which of them vary the least from season to season.


Until next time ... James

A Note On The Method For Choosing "Our" All-Star Team

First of all, my assumption here is that "our" All-Star Game is to be played by the players who are the best at their positions right now, and whose talent limits, if as yet not completely established, are likely to either stay the same, or improve (barring injury).

Let's leave the Hall of Fame in Cooperstown. And leave to the HOF too the players who, while once great (and are no doubt headed there), must be held to the same standard of excellence as the player who has only two or three seasons in the majors, if he is to play in the All-Star game. After all, we wouldn't roll out Babe Ruth's empty uniform from the HOF to play right field would we?

So, although it happens all the time, even in MLB organizational head-offices, let's not judge who is best right now based on a player's performance from several years ago, or even last year (i.e Gary Matthews, Jr.'s 50 million dollar catch last year ... that kind of thinking like the Angels indulged in with the soon to be 32-year-old Matthews) for that matter. What we are looking for is players who have the best skills right now.

So ... what is a skill ... we think we know one when we see it. And in the case of the guys who are still playing and are probably headed for the HOF, but no longer possess All-Star level skills (and most are still tempted to credit with the skill they once possessed); how do we know when the skill is going ... or gone?

NEXT: What is a skill? Which skills can we establish? Which skills are more important in a game where the talent level of all the players is usually very high? Since we voters can't choose the pitching staff, we're going to stick with the position players' skills, offensive and defensive.

"Finding Lost Runs and Wasted Outs"

Over the last year it's occurred to me that it was time to start writing again, but this time, unlike in grad. school, I'd write about things I really know about and care about. This blog is the start of a new project inspecting baseball; one of the greatest sports ever invented, and one that's great to argue about endlessly.

One thing we can take as a given form the outset is that baseball clubs intend to act rationally in their tactics and strategies. Another is that they often fail to do so. Aiding and abetting them are hordes of employees and old ball players that don't really know how to evaluate what is going on in the game that pays their bills.

One further observation ... the majority of fans crave genuinely to understand the game of baseball; a game that has accumulated more numbers around it than perhaps any other professional sport, and it has been doing so for over 100 years; yet well paid and polished professional commentators feed fans simplistic, outdated, and just plain wrong-headed "truths" about the game. And both of these groups tend to feed each other back and forth, leaving the fans wanting.

Anyway ... there are also intentions, perhaps commercial ones, to this endeavor in the real world. Tools of Ignorance Research and Statistics(TM) is dedicated to aiding clients in ... to coin a phrase ... "Finding Lost Runs and Wasted Outs"(c). A simple truth often disregarded ... runs are what win ball games, and outs are the currency that buys the runs. Twenty seven of them that are spent to get more runs than your opponent. Twenty seven runs that your pitchers and fielders try to extract from the opponent before they score more runs than you. Something to remember always when reading these posts ... this truth should never be far from your mind. It is always in the forefront in mine.

Thanks for joining me here ...


NEXT: All-Star voting has already begun on the MLB website.

Let's have a look, position by position, who's really got the goods this year, and who's probably going to make the starting line-up singing "The Way We Were".

'Til then,


James