The 20-80 Scouting Scale, Translated to Wins

Recently, for the electronic pages of Baseball America, Therron Brockish provided a scouting report from the Arizona Fall League on Boston third-base prospect Garin Cecchini. As part of that report, Brockish graded each of Cecchini’s tools on the 20-80 scale (or 2-8 scale, depending) commonly utilized by scouts, where 50 represents major-league average and every 10 points is equal roughly to a standard deviation from same.

The tools are useful as a concise but meaningful instrument by which to summarize a player’s strengths and weaknesses. Because most players in the baseball universe (including minor leaguers and amateurs, as well) are below major-league average, even a 50 grade is a pretty big deal. Cecchini, for his part, received a future grade of 70 on his hit tool from Brockish and about a 50, give or take five points, on the other four traditional tools (power, speed, fielding, arm).

Owing mostly to how Therron Brockish has 20 years of experience as a scout and how I, Carson Cistulli, have 20 years experience mostly in just feeling ashamed of myself, I have no interest, really, in commenting upon Brockish’s assessment of Cecchini. An exercise in futility, is what that would be. I’m well-enough acquainted with futility already that I don’t need to go seeking it out on purpose.

Nor are the particulars of his report really my concern for the moment. What is my concern is attempting to answer a question that has probably occurred to me somehwat vaguely in the past, but, for reasons that are mysterious, presented itself more clearly because of Brockish’s report. The quesion is this question: “If one takes for granted that Cecchini is likely to be a 70 hitter and a basically average everything-else, what does that mean in terms of his likely value so far as WAR is concerned?” Or, phrased more broadly: “Is it possible to ‘translate,’ as it were, all the grades for the five tools into a WAR value?”

What follows represents a mostly responsible attempt, I think, at answering those questions. Answers have been facilitated greatly by a rough WAR calculator of the author’s own invention, but constructed also with no little help from Bradley Woodrum’s De-Lucker. Note, finally, that I’ve used 550 plate appearances as the baseline for an offensive player, for this reason: a batter with league-average rates in everything and 550 plate appearances produces a 2.0 WAR — i.e. the sort of WAR generally associated with a league average player.

This very crowded table (where HRC% represents home-run rate on contact and everything else is pretty self-evident) provides an illustration of the average player such as he appears in the year 2013:

And with that established, below is an attempt at answering the above-mentioned questions.

Hit Tool
Both the Major League Scouting Bureau (by way of Andrew Ball at Fake Teams) and real-live pro scouting coordinator Kevin Goldstein describe the hit tool as a player’s ability to hit for average. Both a multivariate regression (which produces an r-squared of .86) and also just common sense reveal that a combination of strikeout rate and BABIP account for the greatest part of a player’s batting average. Home-run rate is another factor, but less significant and also accounted for by the next tool, power.

The league-average batting average in 2013 was .257; a standard deviation, about 25 points. Using those figures as benchmarks, below is an estimate of the value for each grade along the scouting scale, assuming a league-average walk rate (ca. 8%), home-run rate on contact (ca. 3.5%), and also league-average baserunning and defense. Note that I’ve also attempted to distribute changes in strikeout rate (19.5% average, 6.0% standard deviation) and BABIP (.300 average, .025 standard deviation) evenly.

Value of Every 10 Scouting Points (From 50): About 1.0 WAR.

Power Tool
The sources named above (i.e. the Scouting Bureau and Goldstein) both regard the power tool as roughly descriptive of a player’s ability to hit home runs at the major-league level.

As Mark Smith found in February, the league average home-run rate is approximately 2.5% (or 14 home runs per 550 PA). As Smith also found, a standard deviation is of such a size (about 1.5%) that it prevents any player from recording a home-run rate any lower than about 1.5 standard deviations below the league average (or, about a grade of 35 on power). To address that, I’ve halved the standard deviation for the three grades below 50, so that a 20 and 30 power grade actually mean something. The figures recorded here seem to match, more or less, the thresholds I’ve seen elsewhere for power.

As suggested in the discussion of the hit tool above, home runs can have a substantial influence on batting average at the extremes. Below, for example, is an estimate of all the grades on the power tool produced by changing merely the player’s home-run rate on contact (3.5% league average, 2.0% standard deviation) — and, again, assuming league-average everything else.

What one finds is that batting average increases a full 50 points between a player with 20 power and one with 80 power without altering strikeout rate or BABIP, at all. This is a reality of the hit and power tools, if one defines them in a particular way: they interact.

I will not speak to which way is right or wrong, necessarily; however, it seems as though the objective in using the tools as an instrument is to isolate different aspects of a player’s overall physical abilities. As such, perhaps a different way to assess power is to assume a lower BABIP for each jump in power, which is what is occurring in the table below.

Though not intentional, a byproduct of this second method is actually repesentative of how power works. Frequently, batters will produce high home-run rates because a greater percentage of their batted-balls are fly balls. While producing more home runs, fly balls also produce lower BABIPs than line drives or ground balls.

Value of Every 10 Scouting Points (From 50): Either about 0.9 WAR or 0.5 WAR.

Run Tool
Speed or running or whatever one calls it precisely is relatively easy to measure: one uses a stopwatch. Our concern for the present moment, however, is to estimate what that raw speed might be worth in terms of runs and wins. At this site is housed a metric (BsR) that combines runs produced from stolen bases (wSB) and runs produced by other baserunning acts (UBR). Is there a perfect correlation between those figures and raw speed? Likely not. Baserunning production is likely a combination of raw speed and “instincts” and, finally, opportunities.

For the moment, however, we’ll use BsR as a proxy for speed. League average by that metric is zero by definition; a standard deviation, about 3 runs. Using those figures, below is an estimate of the various speed grades (as they relate to baserunning exclusively and not, for example, defensive range or BABIP).

Value of Every 10 Scouting Points (From 50): About 0.3 WAR.

Fielding and Arm Tools
Just as with baserunning, there’s a disconnect between the actual physical skills of fielding and the precise value, in runs or wins, which those skills are likely to produce. For that reason, I’ve made no attempt to separate the differences between the fielding and arm tools. Also for that reason, I must concede that what we’re considering here are proxies for the tools, and not any sort of objective expression of the tools themselves.

The move on this site recently to package positional adjustment and UZR into one position-agnostic metric (called Def and described more thoroughly by Dave Cameron here) has been helpful in terms of comparing defensive production. It’s been clear for a while that Brett Gardner, for example, has been as valuable in left field as many defenders are in center. In fact, Gardner has recorded about +7.5 Def figure for every 150 games he’s played — or, roughly what a +5 center fielder would post over that same interval. Meanwhile, even a slightly below-average shortstop like Mike Aviles or Jamey Carroll or Jed Lowrie has still produced positive defensive figures cumulatively over the last three seasons.

By definition, the league average fielder records a defensive value (again, fielding plus positional adjustment) of zero. The standard deviation is about 10 runs per annum. Below is an estimate of how those figures equate to the scouting grades.

Value of Every 10 Scouting Points (From 50): About 1.1 WAR.

Summary with Many Caveats
If I haven’t stressed it enough above, let me say it here: this is not intended to be a definitive work, but rather a rough attempt to provide some clarity on the actual significance, in terms of wins, of the various scouting grades for each tool. It’s come to my attention that, even if scouts do not always use grades precisely as they relate to the league average and standard deviations as those figures exist in major-league baseball in 2013, it’s generally the case that scouts understand each other so far as the significance of those grades is concerned.

Ultimately, that’s the goal of any sort of language — to communicate meaning. Part of knowing French, I’ve learned, is knowing not how to speak what might be considered “proper” French, but how to speak it like an actual French person does every day. (Ingeniously, I’ve solved the problem by learning neither kinds of French.) There are idioms and expressions and plays on words that are opaque to someone who has only learned the language in a classroom.

The scouting grades are very possibly not unlike any other language. My limited exposure to the scouting world suggests to me that individual scouts are not anxious about the exact league-average BABIP or the standard deviation for 2013 of home-run rate on contact. Still, it appears as though an understanding exists of the difference between a 40 and 60 hitter, or 20 and 50 runner. This post likely isn’t for that crowd, but rather for those of us (the author very much included) who appreciate seeing that sort of thing rendered objectively. If nothing else, it allows for a starting place for translating the grades on a player’s tools into something concrete — like for Garin Cecchini, who, as a 70 hitter and average everything-else, would likely produce about a 4.0 WAR.

Finally, by way of reference, here’s a summary of the findings above:

*Above or below major-league average, that is, meaning the ceiling for a player with 550 PAs is ca. 10-12 wins.