Bizarre twisty argument about medical diagnostic tests

by Andrew Gelman on August 13, 2010 · 5 comments

in Health Care,Politics Everywhere

My cobloggers sometimes write about “Politics Everywhere.” Here’s an example of a political writer taking something that’s not particularly political and trying to twist it into a political context. Perhaps the title should be “political journalism everywhere”.

Michael Kinsley writes:

Scientists have discovered a spinal fluid test that can predict with 100 percent accuracy whether people who already have memory loss are going to develop full-fledged Alzheimer’s disease. They apparently don’t know whether this test works for people with no memory problems yet, but reading between the lines of the report in the New York Times August 10, it sounds as if they believe it will. . . . This is truly the apple of knowledge: a test that can be given to physically and mentally healthy people in the prime of life, which can identify with perfect accuracy which ones are slowly going to lose their mental capabilities. If your first instinct is, “We should outlaw this test” or at least “we should forbid employers from discriminating on the basis of this test,” congratulations—you’re a liberal. People should be judged on the basis of their actual, current abilities, not on the basis of what their spinal fluid indicates about what may happen some day. Tests can be wrong. [Italics added by me.]

By the time Kinsley reached the end of this passage, he seems to have forgotten that he had already stipulated that the test is 100% accurate. Make up your mind, man!

Also, what’s that bit about “congratulations, you’re a liberal”? I think there are conservatives who believe that “people should be judged on the basis of their actual, current abilities.” Don’t forget that over 70% of Americans support laws prohibiting employment discrimination on the basis of sexual orientation. I don’t think all these people are liberals. Lots of people of all persuasions believe people should be judged based on what they can do, not who they are.

We’re always hearing about the problems caused by political polarization, and I think this is an example. Medical diagnostics are tough enough without trying to align them on a liberal-conservative scale.

P.S Kaiser has more on that “100% accuracy” claim.

{ 5 comments }

Laura August 13, 2010 at 7:23 am

Just a hunch, but perhaps he means ‘liberal’ in the way it is used everywhere in the world except the US, to mean the opposite of authoritarian (rather than the opposite of conservative). It makes a lot more sense if you read it like that.

Wonks Anonymous August 13, 2010 at 12:42 pm

Right, because outlawing and forbidding is precisely the kind of thing that authoritarians don’t do.

Any Mouse August 13, 2010 at 2:19 pm

Just to clarify, while Kinsley doesn’t say this, the test does indeed show that 100% of Alzheimer’s patients and people who later developed Alzheimers had the protein the test looks for in their spinal fluid.

But so did about a third of subjects who have not yet developed any Alzheimer’s symptoms. So it’s actually rather far from 100% accurate by current data.

Further, even tests that are somehow 100% accurate can be performed incorrectly, and records of tests can be incorrectly handled.

HD Carroll August 13, 2010 at 5:35 pm

I wonder if he meant to suggest that *using* tests in this manner would be wrong, or that *testing for this purpose* would be wrong. But, as long as the employer could still fire them when they could no longer do the work, sure, no problem.

Dubi August 15, 2010 at 3:00 pm

“Lots of people of all persuasions believe people should be judged based on what they can do, not who they are” – but this isn’t about judging people according to what they can do or according to who they are – but according to what they’ll be able to do in the future.

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