Okay, there is no way to measure how far players CAN or COULD run (when they played) across left or center field.
BUT WE DO KNOW how many balls they got to and caught. We can measure that and make it a stat,
It is called "range factor" - it was developed by Bill James. Here is how it is calculated, which is not something invented by WIS or SIM baseball:
https://en.wikipedia.org/wiki/Range_factor
So we are now rating a player's fielding range, rightly or wrongly, on what they actually DID in real life, not how good they looked running one time (see the discussion between Brad Pitt as Billy Beane and his scouts early in the movie "Moneyball" for why the "eye candy" test is not a good way to evaluate players).
The letter grades given for range - as several people explained in another thread - is the measure of how good a player's range factor (or fielding percentage for the fielding grade) was COMPARED TO OTHER PLAYERS IN THE SAME POSITION IN THE SAME YEAR.
So go to the Draft Center, click on OF to search for an outfielder. Now, click on one of the areas for searching a player and go down to "range" and then put in the numbers 8 and 12 - to get only players with B range or higher - better than Bo Jackson in 1989. Put "1989" in the year, so we get only those players.
You will see that 43 players come up - Barry Bond, Kirby Puckett, Lenny Dykstra - actually Dykstra comes up as four different iterations, so we really have 40 players.
So 40 players had more putouts and assists per inning played in the outfield than Bo Jackson did in 1989, IN REAL LIFE. THAT is why he is a C range for that year.
d_rocks97:
In 1894, Hugh Duffy played 1060 innings in the outfield. He had 315 putouts and 27 assists. He made 27 errors for a fielding percentage of .927. His range factor per 9 innings played in the field was 2.90. These stats come from:
http://www.baseball-reference.com/players/d/duffyhu01.shtml
WIS lists Hugh Duffy 1894 as C- field, and A range.
Now when we search for 1894 OFs with range factor of A or A+ - meaning we click on "range" as a search variable and put in 11 and 12 as the parameters, we get 7 players with A range.
Let's pick one to compare him with Duffy. Billy Hamilton: In 1894 Billy Hamilton played 1149 innings in the outfield.He had 370 putouts and 15 assists. He made 15 errors. His fielding percentage was .963. His range factor per 9 innings played in the outfield was slightly better than Duffy's: 3.02 - range factor being putouts plus assists calculated here for per 9 innings played, so 3 a game as opposed to 2.90 for Duffy, which is pretty darn close, leading to them having the same range factor for that year. But Hamilton is listed as a "B" in fielding, as opposed to "C" for Duffy, because his fielding percentage as 36 points higher - indeed he made 12 fewer errors.
http://www.baseball-reference.com/players/h/hamilbi01.shtml
There is no magic here. It is all based on real life stats of what the players did in the year in question, and the grades are comparative with others from that same year, and so corrects for different playing conditions over time - as in the use of better gloves today has led in a linear direction toward higher fielding percentage for over a century. So a "B" in 2015 is compared to poorer fielders, and better ones, in 2015, not to how well someone fielded when gloves were primitive.
Let's look at a poor fielder from 1894 now:
If I look for a "D" range - I put 2 and 3 - D and D+ - as my parameters for 1894 outfielders - I get 11 players.The worst who played nearly full time was Tuck Turner. He played 620 innings, had 140 putouts and 7 assists, and made 16 errors. His putouts+assists per 9 innings (range factor) in the field was 2.13, compared to 2.90 for Duffy and 3.02 for Hamilton. Almost a whole out difference per game, or 150 outs per seasons. A lot. His fielding percentage of .902 was poor even for those days. His 16 errors in a little over half the number of innings that Duffy played making 27 makes Duffy look pretty good by comparison.
This is why Hamilton is a B field, Duffy a C, and Tucker a D. And the range factors are also significantly different for that year for those three players - Duffy and Hamilton about even, a slight edge to Hamilton, with Tucker's being very poor. So he is also a D field.
THAT is how this is calculated and I do not see how there is any fairer way to do it than to use what ACTUALLY HAPPENED IN REAL LIFE. Unless you want to rely on video (which is not a one-to-one perfect reproduction of what happens, but a video representation of it, with the digital or film vision having its own speed which can affect how fast someone seems to be going when we look at it by the way - see the Magritte painting "This is not a pipe", or read Walter Benjamin's "The Work of Art in an Age of Mechanical Reproduction for an introduction to these issues.).
So that is how the fielding grades are determined. If you look up any players from a more recent year - 1989 or 2015 or whatever, compare their fielding percentages and their putouts and assists per inning it will be clear why one player is a B or C instead of a D, and why their range is A, B, C or D compared with others from that same year. Period.