• Black clouds: imposed from without or imagined from within?

    When you’re a resident, you spend a huge amount of time with a small number of people. You get to know them very, very well. Sometimes, you even start to imagine things about each other.

    One of the most pervasive beliefs of residents is the existence of “black clouds”. These are residents who carry bad luck around with them. You’d be surprised how quickly people can get this reputation, and how quickly it can spread. “White clouds” on the other hand, have a reputation for easy call nights and little work.

    One of the debates I used to have with friends, however, was whether these reputations were earned or imagined. Did “black clouds” really have more work, or were they just less efficient? Did they have bad luck, or were they just better complainers?

    This came up last night while I was having a drink with a friend. On Monday night, you can fill up your growler at Rock Bottom Brewery for $5! On Friday, you can do so at Sun King Brewery. Now, that’s a deal.

    Anyway, back to the black cloud. This is an answerable question, and some researchers addressed it in 1993, in a manuscript entitled, “Black Clouds: Work Load, Sleep, and Resident Reputation“:

    OBJECTIVE:Although it is assumed that residents in a specific training program will have comparable experiences, residents commonly perceive that some have consistently more difficult times on call. Such residents in our program are said to have “black clouds.” We sought to determine if these perceptions were related to differences in real work load.


    METHODS:We collected data about the on-call experiences of our first-year pediatric residents (PL-1s) for 358 days (1355 on-call experiences) during the 1984-1985 academic year. Every PL-1 (n = 19) reported the following data the morning after each night on call: hours of sleep, number of admissions, total number of patients, number of deaths, number of transfers to the pediatric intensive care unit, number of delivery room trips, and a subjective assessment of work load, using a three-point scale. The reputation of each house officer was determined by asking all residents in the program (PL-1s, PL-2s, and PL-3s) to rate each other three times during the year regarding how hard they worked on call.

    What an amazing study. They collected data on every call for an intern class. Their data collection was near perfect, missing only two calls. They collected perceptions of residents about themselves and about each other. They also gathered data on objective data for correlation. What did they find?

    While there were significant differences between how residents perceived their own workload, there were no differences in their actual workloads. This included the number of admissions per on-call night, the total number of patients they had at the end of their on-call nights, the number of patient deaths, and the number of transfers to the pediatric intensive care unit.

    There were significant differences in how much sleep individual residents got on-call, as well as significant correlations between sleep and perceived workload. Residents definitely differed by the amount of sleep they got on call. Residents who got less sleep were also significantly more likely to perceive their workload as higher.

    Residents with “black clouds” were significantly more likely to get less sleep. However, they did not differ from other residents with respect to actual workload. It turns out that the major prediction of reputation was sleep. But the things that should actually define a “black cloud”, such as admissions or patient load, were not correlated with being a “black cloud”.

    So what is the take home message here? Residents who have a “black cloud” seem to get less sleep than other residents. The question is, however, whether they are getting less sleep because they are working harder, or working less efficiently. In other words, are they really unlucky, with call nights requiring them to stay up more, or are they just reacting to a similar workload in a different way?

    Here’s what the researchers concluded:

    These data confirm that some residents do have a black cloud; they consistently sleep less than their peers, perceive that they work harder, and develop a reputation for having more difficult on-call experiences. The data also demonstrate that during the course of a year there are no differences in most other variables that might affect sleep. We believe, therefore, that the differences among residents are self-generated: black clouds come from within.

    I have to agree. Black clouds are imagined and self-imposed. Residents shouldn’t be proud of them.

    • Aaron
      I chuckled at above. I recalled reading this way back, and amazingly, dug it up. As all of us who recall training, it is a right of passage to idenify the unlucky “black clouds.”

      Converse finding:


      • Brad,

        That study was significantly smaller and had some methodological issues which make it less compelling. That may be why it was published as a letter. These include:

        1) Much smaller sample size, and far fewer call nights
        2) An uneven distribution of call nights between groups. Why was this so?
        3) The analyses were far less sophisticated.

        • Come on guys! What would be the plausible theory of “black” or “white” clouds anyway? Don’t we all know this is silly? Why is this even journal material? Or am I missing something?

          • @Aaron: of course, but I reference only to demonstrate that the Internal Medicine guys are as nuts as the pediapods.

            @Austin: a) 100%; see above, b) they say in baseball there is no such thing as a rising fastball, or in poker, a hot hand. Hooey. Ever get woken up at 3AM by a nurse, who from your view, was placed on this planet to torture you and ruin your life….every night for a whole month. aka, “The black cloud.” Yes, its real, dont ever question it, sure as the sun rises. Just ask Aaron. 🙂


          • You’re missing the fact that doctors can obsess over insane things.

            • I despair at the degree of magical thinking.

            • I think that sleep is a great way to measure this. Having worked full time through both undergrad and med school, I had mastered the art of falling asleep and waking immediately. A lot of people took a long time to master that. Some people just worry too much to sleep on call. Thus, I think that the black cloud thing is both objective and subjective.

              @Austin- Well, yes, but every third night w/o sleep for a few years and your thinking can get a bit magical, even paranoid too, at 3:00 AM.


            • I’ve done my own experiments in long-term sleep deprivation. I know enough about it that it is utterly insane that anyone in the medical field is put under those conditions and that patients are seen by such zombies. That this is a good idea is more magical thinking.

            • In some ways it is, but on my last call I got a major trauma brought to my OR at 3:00 AM with almost no warning. I couldn’t tell that patient I was tired, I had to function. In residency, we figure out who can and who cannot do that. I think that things were probably a bit overdone in my day, residents have it much easier now. OTOH, it is clear that my new hires are much less ready to work on their own than we were when we left my residency. They have not seen nearly the number of cases.


    • Regardless of the accuracy, plausibility or the value of this study, doesn’t it seem unfair to casually assign blame based on sleeping habits?

      Clearly some people sleep more easily under adverse conditions, stress, etc. Is suggesting it’s their own fault appropriate.

      I travel a great deal for work, and I almost always sleep poorly on the first night in any hotel stay. After the first night I sleep much better. I’m guessing it has something to do with being in a strange place that isn’t so strange after the first night.

      But is that a character flaw?