Pictures and Steroids

When people talk about steroids, they tend to talk about pictures like those below. Maybe they don’t use an actual picture, but the point is clear: the rate at which an extreme achievement—like home runs—has changed recently. And that change coincides with a possible increase in steroid use by players.

Rate per year

Because the shift in the 1990s was so dramatic, it’s hard not to wonder what happened. There is no denying that home run balls are flying out of the park more than they used to, which makes it hard to know why steroid skeptics, such as myself, do not acknowledge steroids to be the cause. Yes, Juiced and Game of Shadows tell us that steroids were rampant in the locker rooms of MLB teams during the home run boom. I really can’t argue with the fact that some players may have taken steroids. As to how much and what effect they have had on hitting power I still don’t know. It’s going to take more than accusations from Ken Caminiti, Jose Conseco, and anonymous sources to convince me of player guilt. Regardless of whether or not players used or not, I’m still not convinced that steroids, or any other PEDs, have much to do with the increase in offense. Here are some reasons not to blame the surge on steroids.

Steroids ought to impact both sides of the ball. If there are benefits, both pitchers and hitters will reap them. Recent testing has busted both pitchers and hitters. It is possible that batters benefit more than pitchers, though. So, this reason is not all that powerful, although I would like to see better arguments for the asymmetric effects of steroids on hitters and pitchers.

Also, the introduction of homer-friendly ballparks may have facilitated the home run surge, but it’s not enough. The balls are still flying out of the big places too.

Expansion is the explanation that gets little attention, yet I believe it is the most important factor for the power surge. The rise in home runs coincides with the expansion of the leagues in 1993 and 1998, which has increased the league by more than 100 players a year—a minimum of four 25-man rosters.

The late evolutionary biologist Stephen Jay Gould put forth a novel theory of extreme achievements competitive environments. His idea was that as the variance of the quality of participants shrinks, opportunities for great performances diminish. Being an avid baseball fan, Gould used baseball as his example. He argued that because MLB was being populated by better baseball players, great achievements, such as hitting .400, were decreasing. You see, very good players dominate very bad players, and as the very bad disappear from the game, the very good can no longer rack up good performances against them. Expansion has the effect of letting in the riff-raff for baseball’s elite to exploit. And we can see that as evidence of the inferior pitching entered the leagues that pitchers began to hit more batters. As the graph above shows—did I forget to mention it was a digram of the hit batter rate, not home run rate, over time?—the current era of baseball could just as easily be referred to as the hit batter era rather than the home run era. And most certainly, no one believes steroids cause pitchers to hit more batters—well, maybe it’s roid rage, but I don’t buy that.

Below is a graph of the hit batter and home run rates since 1960. They track together somewhat, but more importantly, they both shoot up in the 1990s, which is what Gould’s theory predicts.

HBP (HR) Rate per year

Furthermore, we can examine Gould’s hypothesis by looking at the talent distribution of hitters and pitchers over time. The graph below maps the coefficient of variation (standard deviation/mean) of batter OPS and pitcher ERA by decade relative to the 1920-2005 average.

CoV of Baseball Talent

The higher the bar, the greater the distribution of talent and the greater the opportunity for great players to dominate poor players. It’s clear that the distribution of pitchers has been rising over the span that both home runs and hit batters have increased. The direction of this effect is exactly what we would predict, and the change is as dramatic as the change in home runs and hit batters.

Most certainly, this does not mean that steroids have not influenced the game. I just think it’s incorrect that there are no other plausible explanations for the changes in performance. Personally, I don’t think steroids have had that much of an effect, even if players have been taking them, but that is just my opinion. Furthermore, I believe Art De Vany is right.

Addendum: David Pinto noticed the effect back in 1994.

Further Addendum: My follow-up post.

20 Responses “Pictures and Steroids”

  1. Dave Berri says:

    I also buy the Art De Vany story. One point he makes is that it is not at all clear that taking steroids would help a person hit more home-runs. This is a sport science issue — outside my area of expertise — but if true, would render the issue of whether Bonds took steroids or not meaningless. If steroids do not help you hit home runs, what difference does it make?

    I think your reference to Gould is right on as well. Expansion would be a more reasonable explanation for why players are hitting more home runs.

  2. David Pinto says:

    Thanks for this article. It confirms a theory of mine that I wrote up in The STATS Baseball Scoreboard 1994. I showed at the time that expansion spread out pitching more than hitting (see page 90). I also pointed out that the baby bust was a contributing factor.

  3. David Pinto says:

    I’ve put up a PDF of my article from 1994 in this post.

  4. Larry says:

    This is obviously testable – compare the HR rates off the best pitchers over eras. If the increase is from the best hitters dominating the worst pitchers, they should be achieving similarly over the best ones.

    Also, couldn’t Hit batters be the body armour/crowding the plate effect, not a decrease in pitcher skill? I see a lot of HBPs these days where I think, ‘gee he didn’t even try to get out of the way of that slightly inside pitch’. I don’t remember that being the case as a kid 20 years ago.

  5. JC says:

    Thanks David,

    That’s really cool. I wish I had seen that essay.


    That is testable, but one pain of a test. I leave it for someone else. :-) Body armor probably contribute to hit batters, but I don’t think it explains much. The neat thing here is that Gould’s theory predicts both the rise in HRs and HBPs.

  6. Mike says:

    Dave, I’m not sure this disproves the theory that steroids helps hit home runs. Look at DeVany’s article, for example, and check out the HR/AB rates for those guys. Why did Bonds, Sosa, and McGwire get so many more home runs during ages in which they should have statistically been trending downwards in power and production? Am I to believe that all three of them were statistical abnormalities for which aging doesn’t have the same effect it has on other hitters?

    Personally, I’d like to see a trend line of HR/AB at parks whose dimensions have stayed the same over the years. I can’t help but wonder what kind of effect the population of ballparks had on the HR hitters.

    I firmly believe in the ability of steroids to contribute to athletes building more muscle and becoming faster and stronger at the plate… which is why I’m shocked that this evidence points towards no visible increase in home runs over time. While Maris and Mantle and Williams were probably pretty buff guys, I just don’t see how they could compete statistically with some of the bulked up monsters of today.

  7. Phil the Brit says:


    This is thoughtful analysis, but let me throw in a nugget of historical comparison from the game of cricket.

    Perhaps hit batters follows an upswing in homers. In other words, pitching at the batter was a tactical response to the home run blitz.

    This would mirror England’s desparate attempt to contain the great Australian batsman Don Bradman in the 1930s. The tactic was dropped following an unholy row that followed, which even threatened to sever diplomatic relations between the two countries.

    Diplomacy notwithstanding, the tactic worked, and England beat the Australians in a series for the only time whilst Bradman was part of the Australian team.

    If Gould’s theory holds, other records should be tumbling too, not just homers.

  8. George S says:

    Very interesting article. I would think that the increase in HBP and HRs is only partly the result of adding more pitchers through expansion. I do not notice any significant spike in HBP during the expansions in the early 60s nor in 1977, when Seattle and Toronto were added to the AL. Plus the player pool today is much more international than during those expansions. If anything, the ML talent level was diluted much more then than now, when you can get quality players from Asia as well as Latin America. Lastly, expansion during the free agent era spreads out the talent much more than in the earlier expansions, when new teams got the dregs and struggled for years to become competitive. This means that today those 40-50 added pitchers are not concentrated onto 3-4 new teams, where they have to pitch a lot of innings, but are spread around more teams and can be used more efficiently, in mop up roles for example.

    One factor that I feel impacted the HBP/HR rates more was the constantly shrinking strike zone during this period. Once the strike zone got to be about 3×3 inches, batters did crowd the plate, and pitchers were forced to throw more pitches in the hitting zone. Now that the strike zone is expanding somewhat, or at the very least getting more consistent, you should see HBP go down as well as HRs.
    Defining the strike zone properly and consistently favors the pitchers, and when the umpires took it upon themselves to interpret the SZ as they saw fit, you saw the increase in both HBP and HRs.

  9. Skip says:

    JC: Another implication of JC’s theory, I think, is that the age of relief pitchers should have increased during the 1990s, relative to the age of an average player. Mike Remlinger, anyone? That too, is testable, and perhaps a bit easier to execute than the bifyrcated HR implications. Although one should consider this implicaiton of the latter – since the best pitchers also face poorer hitters on average, their HR rates should fall as the distribution of talent spreads. So HR rates vs. pitchers should diverge in the 90s: the best pitchers dish out fewer, and the worst dish out more. This means the two should approximately cancel out, which, as DeVany notes, leaves the extreme HR rates jumping up, while the effect on the average HR rate is muted.

  10. fvreg says:

    I agree that expansion dilutes the talent pool, but shouldn’t the influx of foreign-born players offset this expansion? In the 1980′s, the vast majority of All Stars were American. That is certainly not the case today.

  11. Rick says:

    As an economist I did not find your arguments convincing. In fact, I’m not sure the data given even supports those arguments.

    For example, you mention that HR rates and HBP both went up in the 1990′s, but the expansion years (1993 and 1998) don’t appear to be significantly different from the years around them and the greatest increase in the home run rate would appear to be in 2001. How does expansion explain that data?

    Furthermore, the coefficient of variation for ERA continues to rise in the 2000′s. Why would expansion in 93 and 95 cause continued and increasing dilution of talent year after year into the 2000′s?

    Finally, you seem to assume that the rate of HBP corresponds inversely to the talent of the pitchers. Has this assumption ever been tested statistically? In my years of observing baseball I have noticed that some of the best pitchers in baseball have reputations as “headhunters”, i.e Roger Clemens, Pedro Martinez and Don Drysdale.

  12. James R says:

    The steroids doesn’t help you hit home argument never made sense to me. I’m not a scientist but logically it seems like it would. We aren’t talking about casual players taking steroids, we are talking about accomplished major league ballplayers which statically is already a very small and rare population. Then you add the fact that a small change can have an outsized effect. For example, the difference between a homerun and a fly ball out is only a couple of feet or less. If a person that could hit 50 home runs in 500 at bats with 100 warning track outs could just change 20% of the outs into homeruns, well, voila! Same goes for the Ben Johnson effect. Winning or losing the 100 meter dash is a difference of tenths of a second in accomplished athletes. Any extra strength, even a small amout could make an also ran a champion.

  13. Bob says:

    It seems to me that taking a (reasonably) outlying stat like HBP and using it to decide that pitchers are worse is a real stretch.

    If you want to decide whether or not pitchers are better or worse, why not use the things that they control: walks, strikeouts and HRs (and maybe not even HRs due to the smaller modern parks)? I’d bet that the ratio of strikeouts to walks has shown an increase since the 20s.

  14. Chris says:

    Per Bob’s discussion points … I think he is on to something. Strikeouts have spiked in the HR era, too. Stolen Bases have plummeted, as well. The nature of the game has changed from “small-ball” or “Billy-ball” (from the days of Billy Martin managing the A’s) to “Chicks dig the long-ball”.

    Smaller parks, expansion, HBPs, all have their place. Does anyone track broken bats? Bats have improved in technology tremendously over the years.

    All very interesting!

  15. Bob Loomis says:

    It would be interesting to track Bonds’s home runs by pitcher during his record season. Who were they and what were their records that season (compared with their pitching in other MLB seasons, if possible)? The same could be done with other power hitters … It’s possible in my view that Bonds’s greatest strengths are his eyesight and his bat speed … seems like steroids might have helped that bat speed, judging from steroid use by top sprinters? Or am I on the wrong track there? Seems to me he’s swinging the bat a bit slower this year, but that could be just my perception or a factor of aging.

  16. Roy Henninger says:

    So now that MLB is testing for steroids, and the influence of steriods is presumably diminished, we can continue to look forward to further assaults on the single season home run record?

  17. Paul Deuter says:

    If the difference is skill and not strength, then we should see an increase in batting averages too. And perhaps more hitters flirting with .400. If anything, batting averages seem to be down. I agree however that the effect of steroids is overblown. In recent years, hitters have been pumping iron, eating much more nutritious food and benefitting from improved equipment. Using steroids is a part of whole regimen and it is near impossible to determine the isolated effect of one part of the regimen.


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