Troubled by Heterogeneity?: A simple example to illustrate why we might or might not be

Fresh perspectives on modern understandings of heredity and development over the life course can be opened up by examining the ways that research and application of resulting knowledge address—or suppress—heterogeneity in a range of senses (including individual particularity and variation around a mean).  Let me illustrate why we might or might not be troubled by heterogeneity through a personal story that involves the simplest sense of heterogeneity, namely, a group made up of two distinguishable subgroups.

At my annual physical when I turned 50 my doctor recommended a regimen of half an aspirin a day to help prevent a stroke or heart attack.  Not long afterwards I learned that some fraction of the population is resistant to aspirin—it does not produce the desired anti-platelet effect.  This subgroup is, however, still subject to aspirin resulting in an increased risk of serious gastrointestinal bleeding.  Could I find out if I was in the resistant fraction?  My doctor informed me that health insurance companies do not consider testing to be a justified expense for healthy subjects.  It was, he advised, up to me to decide whether to take the daily aspirin.  Some Internet follow-up on my part revealed that testing for resistance is possible, but is undertaken only when patients under treatment for a cardiovascular attack do not seem to be showing the anti-platelet effects of aspirin intake.  Would I devote energy to find others with similar concerns about their aspirin-resistance status and agitate for access to testing?  No—I went along with the health insurance company’s determination and followed the doctor’s advice to make a personal choice, in this case, not to take the daily pill.

With hindsight, my decision was a good one—recent research indicates that in all healthy subjects the decreased average risk of a cardiovascular event might not outweigh the increased average risk of gastrointestinal bleeding (Seshasai et al. 2012).  Yet, these newer findings aside, consider my experience at the time.  In the doctor’s initial recommendation, aspirin-resistant and normal subgroups were treated as a single group of over-50s, all of us subject to the same positive trade-off between cardiovascular and gastrointestinal risks.  The doctor could have been troubled by the heterogeneity within this group, especially after I raised my concerns.  Instead he invoked the rhetoric of patient choice and the constraints of the health insurance system.  I entertained the possibility of joining with others to agitate for testing to determine which subgroup we belonged to.  In the end, I complied with my doctor’s framing of my position, namely, I should see myself as a member of an over-50s group subject to a degree of uncertainty about the positive trade-off.

In this story we can see the three parts of a broad contention—

•  Research and application of resulting knowledge are untroubled by heterogeneity to the extent that populations are well controlled—As the story conveys, I did not comply with my doctor’s initial recommendation, but accepted his subsequent advice.

•  Such control can be established and maintained, however, only with considerable effort or social infrastructure—The authority of medical professionals was not sufficient to achieve my compliance, but the rhetoric of patient choice and the reimbursement guidelines of the health insurance system eventually were.

•  The interplay of heterogeneity, control, and social infrastructure provides an opening to give more attention to possibilities for participation instead of control of human subjects—The Internet gave me a means to go beyond the consultation with my doctor.  It would have been my first port of call if I had embarked on a journey of finding whom to collaborate with to agitate for change in the guidelines for aspirin-resistance testing.

HetContention

Figure 1. Schema that summarizes the contention in the text.  The contention applies both to the modern understandings of heredity and to interpretations of science in Science and Technology Studies (STS). (Colored text narrates the connection between terms linked by the curves. Zigzag lines indicate a tension or contrast, e.g, populations are harder to control if members of the population are able to participate in ways that draw attention to heterogeneity within the population.)

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One thought on “Troubled by Heterogeneity?: A simple example to illustrate why we might or might not be

  1. Pingback: Alternation between complexities of situation studied and the situation of the studier: A series of writing projects | Intersecting Processes

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