The Canseco Effect?

The economists Eric Gould and Todd Kaplan have used data to evaluate Jose Canseco‘s claim that he taught many teammates to use steroids and growth hormones. “[A]fter playing with Canseco, players hit more home runs and otherwise boosted their numbers in the areas most affected by steroid use,” writes Ray Fisman in Slate. Furthermore, “the Canseco effect disappears after 2003, when baseball instituted random drug testing and punishments for those found guilty.” [%comments]


JC Bradbury challenged the conclusions of Gould and Kaplan based on their curious approach to the study. His challenge can be found here:

Both the study and the rebuke are more than 18 months old. Slate needs fresh material.

Drill-Baby-Drill Drill Team

Ironically Jose Canseco has an identical twin brother, Ozzie Canseco, who while a career Triple A player, was never good enough for the Major League.

If Ozzie stayed 'cleaned', we have a built in scientifically controlled experiment. But apparently he also was arrested for illegal drug possession of anabolic steroids.

It seems it is more than genes and drugs that make a Major League player....Perhaps Personal Drive?

Twins are natures built in double blind controlled studies.


"[The players who played with Canseco] boosted their numbers in the areas most affected by steroid use."

When one of these numbers is RBI, the study is highly suspect.

Thanks to JC Bradbury, who's article should be required reading for anyone reading the Gould and Kaplan article.

Here's an alternative way of quantifying the effects of PED use:


For those who don't want to read the whole thing, basically the rebuke was that Canseco's teammates gained additional at-bats when he went to another team. The guys doing the study looked at things like total home runs rather than home run rates (per at bat).

Phil Birnbaum

I third the motion to read Bradbury's rebuke. My own comments are here:

Baseball Purist

I'm still waiting for the "Aaron, Mays, Jackson, Stargell Effect" studies.

Seems that this year pitchers are doing incredibly well against teams at the end of a long road trip now that amphetamines (speed) are being tested.

Where are the baseball writers coming out of the woodwork to debunk the drug users of prior eras?

Eric M. Jones

I want to proclaim the value of enthusiastic leaders and associates. I have met a few in my life whose presence and attention inspire people (like me) to do magnificient work and accomplish the seemingly impossible.

All without performance-enhancing drugs, although they would have been a whole lot easier and cheaper.

Rich Walter

Ozzie Canseco was good enough and was in major league baseball.

Todd Kaplan

You can read the updated version of the paper at