Monday, October 15, 2012

Lance Armstrong and False Positives

Well the talk went well.

I'm waiting for the official rating (people fill out anonymous evals), but there seemed to be a lot of interest....and more importantly I got quite a few compliments on the unique approach.  Giving people something new in the "how to get along" genre was my goal, so I was pleased.

Between that and having 48 hours to pull together another abstract for submission to a transplant conference, posting got slow.

It was interesting though....the project I was writing the abstract was about a new test we introduced that saved patients over an hour of waiting time IF it came out above a certain level.  We had hours of discussion about where that should be, ultimately deciding that we had to minimize false positives (times when the test said they passed but a better test said they failed) at the cost of driving up false negatives (when the test said they failed, but they really hadn't).  We have to perform the more accurate test regardless, so it was a choice between having a patient wait unnecessarily, or having them start an expensive uncomfortable procedure unnecessarily.  Ethically and reasonably, we decided most patients would rather find out they'd waited when they didn't have to than that they'd gotten an entirely unnecessary procedure.

I bring all this up both to excuse my absence and to say I was fascinated by Kaiser Fung's take on Lance Armstrong.  He goes in depth about anti-doping tests, hammering on the point that testing agencies will accept high false negatives to minimize false positives.  It would ruin their credibility to falsely accuse someone, so we have to presume many many dopers test clean at various points in time.  It follows then, that clean tests mean fairly little, while other evidence means quite a lot.

I thought that was an interesting point, one I had certainly not heard covered.

Also, as any Orioles fan (or someone who lives with one) would know, I have good reason to want Raul Ibanez tested right now.

More posts this week than last, I promise.


  1. We all intuited Fung's premise at a milder level all along, knowing that people evade detection about many things all the time. But he makes it much more sharply than we usually carry around in our brains. We tend to conclude pretty rapidly that a few positives are indicative of a general cleanness. Fung reminds us that in this specialised situation, that is leaping to conclusions.

  2. If you're looking for some reading to spur you into written action, I throw this your way:

  3. If doping was so deeply ingrained into the cycling culture, then does that not effectively create a "level playing field?" If everyone dopes, then won't that reduce the variation caused by doping vs not doping?

    It seems to me that by proving the prevalence of doping we might find less cause to think of it as cheating. Why did none of the other doping cyclists win anything during any of these 7 years that Armstrong won? Was he just the much better a doper? Or was he a better doped up athlete among doped up field?

    I'm not sure how to phrase it, but there seems to be a statistical question (or a question of scientific method) in there someplace.

  4. Armstrong's statements are now that he used no "unfair advantage," and that may be so. But as you point out, Dave, we are then left with questions without answers. Was he better, better at doping, or both?

    Step back and take the questions to the next level: each sport tries to have an internally consistent set of rules, so that we might measure with accuracy. We can have whatever rules we want - doping or not doping, or the NFL's "you can do 65 in a 55 zone but not 85" rules. That is the theory.

    But as soon as we try to tie all this into real life it falls apart. At that point we suddenly realise it's all arbitrary. Hitting a ball into a hole with a stick? Running faster for 100M, but not caring about 40M or 175M? Making metal wheels on a frame go faster over days with team support? We could have chosen anything. You can only run a good mythology - for that's what the entertainment value is - from within arbitrary rules. Caveat: it is also part of the re-enactment myths for real life that every sport have some figures who play at the edge of the rules. The crowd likes that, too.