The Devil’s Tic Tac

From “Nobody Has My Condition But Me” by Beverly Gage in The New Yorker:

Plus, the longer you stay on it the harder it becomes to stop. Prednisone is sometimes referred to as “the Devil’s Tic Tac”: cheap and available and effective, but at potentially scorching long-term costs.

Great term.

I always find it interesting that The New Yorker changes the titles of its stories for the internet so often. In print, this personal essay was titled “One of a Kind.”

Coffee at Work

[This post was originally written in September 2022. But, update: Yum. My third order just arrived in the mail yesterday.]

The coffee at work has been—for most locations of my training and attending career—terrible. From the burnt “Parks and Coffee” drip sitting for hours on the hot plate during residency to the cheapest K-cups at the imaging center. It doesn’t matter what sweetener or creamer you might add, it was rare to finish the cup once it was cold enough to taste. I’m not a coffee snob. I’m really more of a pragmatist. I don’t have the time or inclination for a long ritual even when working from home let alone the desire to do anything elaborate at work. Walking to the hospital Starbucks is slow and expensive. It’s a treat on the way for an early call shift morning but not something I enjoy doing routinely.

One of my residents shared Cometeer with me. It’s a variation on a coffee subscription (which is itself a variation on the incredible number of subscriptions available these days). I generally don’t like these sorts of things (who wants to remember to pause or cancel?), but I enjoyed the one I tried at work so I gave it a try.

The twist is that it’s a small recyclable cup of liquid-nitrogen flash-frozen coffee concentrate. Add your liquid of choice, hot to the frozen puck or cold after thawing, and you have instant coffee that isn’t, well, instant coffee. I predominantly use it as an espresso shot equivalent for making ice lattes, and for this purpose, it is effective and efficient. And it’s easy to slip in my bag and use on-site. On the enjoyment scale, I put it way above Starbucks’ regular iced coffee and just underneath their shaken iced espresso.



I honestly don’t know if I will continue to subscribe in the future, because it’s not the cheapest. You can cancel at any time and thankfully it’s also easy to spread out deliveries and pause them for months, because there’s no way I would want tons of coffee piling up in my freezer at any given time. I just don’t drink that much. With a $25 new member coupon, the per cup cost is $1.20 per pod (just a bit more than Nespresso pods) and cheaper than what I get at the coffee shop (but also more expensive than nothing, free tea, or the burnt brown caffeinated sludge otherwise available).

So, if you happen to be in the market for a new caffeine source and are interested in trying something new, you can try Cometeer and get $25 off (and subsidize my coffee consumption by the same amount!). Note that this is not a sponsored post; I just wouldn’t mind having cheaper coffee in the future. Also, note that I have literally never done a post like this in this site’s 13-year history. And finally, note that I can only use one referral bonus per order, so alas no matter how many of you choose to buy some I won’t be getting any coffee for free.

Noise in Medicine

Some medical takeaways from Nobel-laureate Daniel Kahneman’s Noise: A Flaw in Human Judgement:

The large role of noise in error contradicts a commonly held belief that random errors do not matter, because they “cancel out.” This belief is wrong. If multiple shots are scattered around the target, it is unhelpful to say that, on average, they hit the bull’s-eye.

I like this line. Some radiologists, for example, over-call questionable findings while others are too cavalier and miss subtle features. They do not cancel out.

In Noise, Kahheman breaks noise down into three big categories: Level Noise, Pattern Noise, and Occasion Noise (each with its own causes and with its own mitigation strategies).

  1. Level noise: The deviation between a single judge from the average judger. For example, some teachers are tough graders.
  2. Pattern noise: The deviation of judges related to a unique or specific situation. For example, a teacher is generally an easy grader but really really likes Oxford commas and tends to grade harsher than average for students who fail to use them.
  3. Occasion noise: Variability related to random irrelevant/undesirable factors (weather, time of day, mood, recent performance of a local sport’s franchise). For example, a teacher grades harsher when finishing up their work from home.

Some doctors prescribe more antibiotics than others do. Level noise is the variability of the average judgments made by different individuals. The ambiguity of judgment scales is one of the sources of level noise. Words such as likely or numbers (e.g., “4 on a scale of 0 to 6”) mean different things to different people.

A massive problem, to be sure, and the reason why radiology trainees hate reading degenerative spine cases (no matter how you grade neural foraminal stenosis, it feels like you’re always “wrong”).

When there is noise, one physician may be clearly right and the other may be clearly wrong (and may suffer from some kind of bias). As might be expected, skill matters a lot. A study of pneumonia diagnoses by radiologists, for instance, found significant noise. Much of it came from differences in skill. More specifically, “variation in skill can explain 44% of the variation in diagnostic decisions,” suggesting that “policies that improve skill perform better than uniform decision guidelines.” Here as elsewhere, training and selection are evidently crucial to the reduction of error, and to the elimination of both noise and bias.

Algorithms are powerful, but for those that assume that checklists and knee-jerk medicine can provide equivalent outcomes, apparently not.

There is variability in radiologists’ judgments with respect to breast cancer from screening mammograms. A large study found that the range of false negatives among different radiologists varied from 0% (the radiologist was correct every time) to greater than 50% (the radiologist incorrectly identified the mammogram as normal more than half of the time). Similarly, false-positive rates ranged from less than 1% to 64% (meaning that nearly two-thirds of the time, the radiologist said the mammogram showed cancer when cancer was not present). False negatives and false positives, from different radiologists, ensure that there is noise.

The massive amount of noise in diagnostic medicine is one of several reasons why “AI” is so enticing. Essentially no one chooses their radiologists, and radiologists are often an out-of-sight/out-of-mind commodity. With our fee-for-service system combined with corporatized profit-seeking and a worsening radiologist shortage, it seems–at least anecdotally–that quality may be falling. These factors all combine to pave the way to make AI tools look even better in comparison.

Later, they go on:

Pattern noise also has a transient component, called occasion noise. We detect this kind of noise if a radiologist assigns different diagnoses to the same image on different days.

This definitely happens. Consistency is hard.

A separate study discusses another human foible, occasional noise related to the time of day:

But another study, not involving diagnosis, identifies a simple source of occasion noise in medicine—a finding worth bearing in mind for both patients and doctors. In short, doctors are significantly more likely to order cancer screenings early in the morning than late in the afternoon. In a large sample, the order rates of breast and colon screening tests were highest at 8 a.m., at 63.7%. They decreased throughout the morning to 48.7% at 11 a.m. They increased to 56.2% at noon—and then decreased to 47.8% at 5 p.m. It follows that patients with appointment times later in the day were less likely to receive guideline-recommended cancer screening.

How can we explain such findings? A possible answer is that physicians almost inevitably run behind in clinic after seeing patients with complex medical problems that require more than the usual twenty-minute slot. We already mentioned the role of stress and fatigue as triggers of occasion noise (see chapter 7), and these elements seem to be at work here. To keep up with their schedules, some doctors skip discussions about preventive health measures. Another illustration of the role of fatigue among clinicians is the lower rate of appropriate handwashing during the end of hospital shifts. (Handwashing turns out to be noisy, too.)

Taking a human factors engineering approach, we know that both patients and doctors will be better off in a system designed with human limitations in mind. For example, not just a deluge of interrupting EHR reminders to ignore, but a system that allows for the right kind of low-friction actionable prompts to be delivered at a useful time during a clinical encounter that is already scheduled in a way to allow for real-time documentation completion without running behind. Wouldn’t that be something?

Concerning metrics:

Focusing on only one of them might produce erroneous evaluations and have harmful incentive effects. The number of patients a doctor sees every day is an important driver of hospital productivity, for example, but you would not want physicians to focus single-mindedly on that indicator, much less to be evaluated and rewarded only on that basis.

See: Goodhart’s Law and patient satisfaction.

Discussion of job interviews and candidate selection has obvious parallels with the residency selection process:

If a candidate seems shy and reserved, for instance, the interviewer may want to ask tough questions about the candidate’s past experiences of working in teams but perhaps will neglect to ask the same questions of someone who seems cheerful and gregarious. The evidence collected about these two candidates will not be the same.

One study that tracked the behavior of interviewers who had formed a positive or negative initial impression from résumés and test scores found that initial impressions have a deep effect on the way the interview proceeds. Interviewers with positive first impressions, for instance, ask fewer questions and tend to “sell” the company to the candidate.

This is an incredibly on-point summary of how most institutions conduct interviews. Those candidates who are good on paper and not painfully awkward during the initial pleasantries basically get a pass. Even when given questions, those answers are often contextualized within the pre-formed opinions. This focus on “selling the program” would even be reasonable if the metrics and data that programs receive were actually helpful at predicting residency success.

Kahneman and his team offer a lot of advice on how to conduct better interviews in the book. Some of it I suspect is too inefficient and awkward for the residency process, but what a lot of programs do (subjectively grade an applicant on a few broad metrics during a committee meeting and then pretend the process is objective) is a bit of a farce.

Summary: highly recommended reading.


Incidental Pain and Suffering

From Matthew Davenport’s upcoming article in AJR, “Incidental Findings and Low-Value Care“:

It is increasingly recognized that incidental findings are incompletely understood, expensive, and surprisingly harmful. Rather than a benefit of imaging, they are usually a harm. They are not sought, the odds of them being important is low, and they create tremendous uncertainty and low-value care.

A good primer on an often unintuitive and yet incredibly important problem in medical diagnostics (both for radiologists and clinicians).

Writing “Content”

I’ve been writing online (“blogging”, cringe) for over 14 years now, and there can be a sometimes strange (and strained) relationship between writing-as-service and writing-as-expression. I’ve mostly written whatever I want, or at least whatever I thought had two or three of this magic combination:

  • interesting to me
  • would be helpful to other people
  • either no one else was doing it or I had an individual (ideally unique) perspective

And yes, sometimes I just wrote whatever.

Over the years, this site has focused on a variety of topics until they’ve covered the ground I wanted to cover or exhausted my interest. I wrote a lot about studying in medical school (choosing books, approaching questions, etc) until I wasn’t interested anymore (not a great financial decision, but hey). I wrote a lot about approaching the residency selection process.

I wrote the book for the Texas JP exam because that test was a stupid hassle and no one had made what I thought should exist. So I did.

I wrote a lot about personal finance specifically for medical students and trainees and especially about student loans, mostly because content on student loans just did not exist at the time (I know, hard to believe). Now it does, and I felt I covered that sufficiently in the book, so I mostly moved on (also not a great financial decision, but hey). I’ll probably return to personal finance again in the future. I still have more to say, but I’d be kidding myself if I pretended even for a second that my opinions are particularly unique or interesting or that this space isn’t being adequately covered (frankly, it’s saturated; there’s plenty of content and almost infinite noise to wade through already).

I’ve written a lot about medical training, radiology, and various topical issues related to organized medicine like board certification (ABR I’m looking at you) or healthcare trends like private equity takeovers. People like these posts. I (still) like writing them. I genuinely think these issues aren’t talked about enough, even though my fly buzzing on the internet probably isn’t going to move the needle much.

I was going through my archives at the end of the year, and I noticed just how much of the writing that I thought was evergreen is slowly aging out. Posts that used to be perennial traffic drivers have eventually lost their mojo. A lot of that may be because “the blog is dead,” and some of it just that Google overall favors fresh content all things being equal, even if the classics are still fire. But some of it is because even things that don’t change quickly sometimes still change slowly. 14 years is a long time on the internet. I guess that’s both a testament to how long I’ve been doing this and also a little sad.

There has never been a shortage of things I’d like to write about. I could easily fill up my days writing full-time, and my collection of potential post ideas and article fragments is comically long. It only gets longer. I get a lot of topic requests, and they’re almost always things I’d be happy to write about given time. But there’s also that unavoidable truth that every yes to one thing is a no to another.

I’d like to have more of my writing be timeless. (Maybe it’s time to go back to fiction too?) We’ll see. I also want to keep being a resource for radiologists and other physician readers, but I also wouldn’t mind writing things that might be interesting to someone who doesn’t work in a hospital. Morgan Housel, who wrote the excellent Psychology of Money, tweeted:

I think “know your audience” can be dangerous advice for writers.

Write stuff you yourself find interesting and entertaining.

Writing for yourself is fun, and it shows. Writing for others is work, and it shows.

One perk of jumping around over time is that I haven’t had to worry too much about audience capture.

As for me, I want you to know this has been fun, and I hope that shows. Thanks for reading.