I have to admit I’m guilty of something. It’s a small thing, not exactly a sin, but I still do it. I’m guilty of trying to compare players across eras. We all do it. We compare Babe Ruth to Hank Aaron. We compare Lou Gehrig to Mark McGwire. We compare Honus Wagner to Derek Jeter. Baseball statisticians have come up with stat after stat that attempts to compare players. Some of them take the time to try to figure out how the eras differ and then try to factor that into the equation. Some of those do a fairly good job of it, and others stink up the joint when they try. So here’s a look at some of the factors that I think have to be considered when trying to compare players across eras.
1. Segregation. This one should be obvious and I have no idea how you factor it in. How much does Lefty Grove not having to face Josh Gibson change Grove’s overall numbers? Got me, coach. And of course it works the other way too. How much does Satchel Paige’s inability to face Babe Ruth in meaningful competition change Paige’s numbers? Again, got me, coach. I think it is important to recognize this is a problem. I simply have no idea how you fix it.
2. Roster sizes. I don’t want to hit this one too hard. If you have Babe Ruth on your team, you’re going to play him a lot. But roster sizes do matter, at least some. The smaller the roster, the less a manager can rest a player and that can create end of season slumps that might not occur on teams with larger rosters.
3. Rules changes. I tend to harp on the pitching change to 60’6″ as a watershed in baseball, but there are a lot of major rules changes that make it difficult to compare players. How would Cy Young do pitching at 50 feet? Well, we actually know he did quite well for a few years, but we don’t know what that means for someone like Walter Johnson. Pud Galvin never pitched a big league game at 60’6″. Could he have been successful there? Don’t know and don’t know how to figure it out. There are other problems like ball and strike count, stolen base rules, etc. My guess is that some of them can be accounted for by looking at before and after stats and seeing how much change occurs (sort of like figuring out how much expansion changes things), but I don’t know you can account for every situation, particularly the mound. I also know this is a much greater problem in trying to factor in 19th Century players.
4. Equipment. How good was Honus Wagner in the field? A look at his basic fielding stats shows he was OK, but nothing special. Some of the newer stats begin to show us just how good he was, but many of the older ones don’t take the difference in equipment into account. When you’re playing shortstop with a glove that looks a lot like my winter gloves, you’re not going to put up fielding statistics that equal those of players with modern gloves. Take a look at modern catching equipment versus the gear of players as recent as Ray Schalk (of 1919 fame). Fielding statistics have gotten better over the years, but much of that is artificial, brought on by equipment changes. Same for batting. Moderns bats are a far cry from the table legs used by guys at the turn of the 20th Century. There’s a wonderful picture of Nap LaJoie that I stuck in above. Take a look at the bat. Now think about a modern bat. Tell me that one factor doesn’t affect stats.
5. Fields. Modern baseball parks are a far cry from early parks. I’m not talking about the distance to fences, that’s easy to factor in. What I’m talking about is the general condition of the playing surface. Wagner talked about picking up a ball and watching a cloud of dust, a handful of pebbles, and the ball all going toward first at the same time. Don’t know how many times that actually happened, but it’s not going to happen at all today. Those uneven fields created more errors and also made normal chances more difficult. I think you can determine the best fielders of the era, but to compare them to modern fielders is difficult enough without worrying about the condition of the playing surface in 1910.
6. Going off to war. Really cuts down on your playing time and is specific to time and place.
Most of what I’ve talked about so far is generally known, and I think statisticians have made good-faith efforts to factor in those things. How much success they’ve had is another question. I don’t know that Win Shares or WAR or anything else adequately accounts for these things, but it’s evident that they are trying. It’s the following two items that I think have been vastly underappreciated by people who try to compare players.
7. Medical advances. You do know that if Tommy John never has the surgery named for him that he never enters a Hall of Fame discussion, don’t you? If that surgery were available in 1935, maybe Dizzy Dean wins another 100 games (or maybe something else goes wrong and he doesn’t). Modern arthritis treatments might give Sandy Koufax another twenty win season. My point is that medical advances change the ability of players to compete just as changes in bats and gloves and fields do the same. I don’t know that anyone has considered this. I also don’t know how you would factor it in, but I think it should be noted at some point.
8. Salaries. Back when I was collecting baseball cards the info on the back sometimes told you what the guy did in the offseason. Most players had to have a “real” job to make ends meet. Most of those jobs weren’t going to enhance your baseball skills. A guy like Richie Hebner dug graves. That might keep him in shape, but didn’t particularly help his batting eye. An old Cardinals pitcher named Ray Washburn sold insurance. Checking actuary tables probably didn’t hurt his eyesight too much, but I’ll bet it didn’t help his throwing motion. With modern salaries making it less necessary for players to have a “real” job in the offseason they have more time to hone their baseball skills, thus making them better players. This doesn’t mean they all do it in the offseason, only that the opportunity is there for modern players, an option that wasn’t as readily available in 1960. Again, I’m not sure how that’s factored in, but it probably should be noted.
So the next time you decide to see if you can figure out which was better, Babe Ruth or Hank Aaron, don’t forget to factor in a bunch of things that don’t always show up in the stats. There are others that I didn’t mention above (like advances in training methods), but these will do for starters. Have fun.