Are you 79½ or 80?

I’m a few weeks away from my 80th birthday, which turns out to be a cultural watershed of sorts — the dividing line between being “in your 70s” and “in your 80s’, which is definitely old age. But that doesn’t actually make a lot of sense: the decades according to the calendar correspond to no natural physiological milestones, especially not ones so very sharply delineated. One period of life shades into another, with relatively long transitions.

The matter isn’t just theoretical, but of great practical significance, as detailed at some length in the New York Times on-line on 2/20/20, in “The Upshot: How Common Mental Shortcuts Can Cause Major Physician Errors: Tendencies like left-digit bias can have life-altering consequences for patients” by Anupam B. Jena & Andrew R.Olenski (in the print edition on 2/21, under the title “Are you 79½ or 80? Your Doctor’s View May be Life-Altering”):

It’s tempting to believe that physicians are logical, meticulous thinkers who perfectly weigh the pros and cons of treatment options, acting as unbiased surrogates for their patients.

In reality, this is often far from the case. Bias, which takes many forms, affects how doctors think and the treatment decisions they make.

Racial biases in treatment decisions by physicians are well documented. One study found that black patients were significantly less likely than white patients to receive pain medication in the emergency department, despite reporting similar levels of pain.

… But a growing body of scientific research on physician decision-making shows that doctors exhibit other biases as well — cognitive ones — that influence the way they think and treat patients. These biases lead doctors to make the same mistakes as the rest of us, but usually at a greater cost.

… In a new study of physician treatment decisions, published on Thursday in The New England Journal of Medicine, we document signs of left-digit bias. This is the bias that explains why many goods are priced at $4.99 instead of $5, as consumers’ minds round down to the left-most digit of $4.

We hypothesized that doctors may be overly sensitive to the left-most digit of a patient’s age when recommending treatment, and indeed, in cardiac surgery they appear to be. When comparing patients who had a heart attack in the weeks leading up to their 80th birthdays with those who’d recently had an 80th birthday, we found that physicians were significantly less likely to perform a coronary artery bypass surgery for the “older” patients. The doctors might have perceived them to be “in their 80s” rather than “in their 70s.” This behavior seems to have translated into meaningful differences for patients. The slightly younger patients, more likely to undergo surgery, were less likely to die within 30 days.

Our study confirms previous work that found doctors are overly responsive to patient age when diagnosing illness, and that showed how seemingly irrelevant factors‚ such as the difference of a few weeks of age, could govern physicians’ decisions about treatment, with potentially life-altering consequences for patients.

And now the crucial transition age of 80 appears again, in the context of COVID-19. From the Healthline site on older people at risk for COVID-19 virus:

Dr. Nagendra Gupta, internist at Texas Health Arlington Memorial Hospital: “In a recent study published in JAMA, which is the largest study on COVID-19 published so far, the case fatality rate was close to 15 percent in patients over the age of 80 as against the average overall case fatality rate of 2.3 percent

Cognitive biases are a recurrent theme on this blog — see the many postings indexed in the Page on illusions postings on this blog — and there’s now a gigantic literature on the subject. There’s an attempt to list all the cognitive biases that have been posited in this giant graphic (which you will need to magnify for more careful study):

3 Responses to “Are you 79½ or 80?”

  1. kenru Says:

    Yikes! I’m a year younger than you are; but now I’m afraid of what’s going to happen in a year when I turn 80. Now I understand why Jack Benny stayed 39 all those years.

    • CP Huxley Says:

      Child actors’ ages can be similarly flexible. In the musical Gypsy, a theatre secretary questions Baby June’s purported age.

      “Say, woman to woman, how old are you?”
      “Nine what?”
      “Nine going on ten.”
      “How long has that been going on?”


    I’m an 81 year old retired physician, a pathologist. I spent many years making diagnoses, some trivial, many cancer.

    Diagnosis is an extremely “right-brained” process, including the diagnosis of cancer. Typically you make the diagnosis of cancer, then you may spend five minutes trying to talk yourself out of it – that’s the “left-brained” part of diagnosis. I was taught this quite explicitly when I was a pathology resident 50 years ago.

    When you have to reverse the process – you don’t know at a glance, so you get the textbook down off the shelf and look at the pictures until one matches up – that’s when you make mistakes. Either you show it to a colleague at the next microscope, or you send it off to a consultant, if the diagnosis is going to make a difference to the patient.

    Lately I’ve been identifying wild flowers using Microsoft Bing’s “Name that Plant” application. It’s remarkable – it sometimes fails to make an identification, but I haven’t had a wrong identification yet (after consulting two or three wildflower books and searching online to confirm the identification).

    I wish I’d had “name that lesion” during my years behind the microscope.

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