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This is a beautiful conjecture! The problem is amusingly circular. Even if you reject the conjure in parent comment, you will be tempted to reduce the number o

This is a beautiful conjecture! The problem is amusingly circular. Even if you reject the conjure in parent comment, you will be tempted to reduce the number of birthday surgeries due to the increased mortality. This will mean that birthday surgeries are only done in even more desperate circumstances which of course will increase the risk. So mitigation of this problem will lead to the percentage increasing even more! Actually, it turns out that it is possibly better if the percentage is high!

Ensorceled 6y ago
Yes, it does really mean you need to dig into actual causation or the law of unintended consequences will bite you in the ass.
faeyanpiraat 6y ago
I do not completely understand your points. Shouldn't hospitals have multiple surgeons? If one of them is on vacation, the other one does the work, and vice versa?
- Galanwe 6y ago
  I don't think surgeons are fongible assets. There is a lot of planning and study taking place before a complex operation. Not to mention most surgeons have specialties.
  - watwut 6y ago
    The long term plans and studied for surgeries can be moved one day forward or backward basically by definition.
    - travmatt 6y ago
      Except if something changes suddenly and surgery is suddenly needed - that’s what makes it an emergency.
  - daniellarusso 6y ago
    A surgeon seems more fungible than a developer, to me. All sorts of standards, compliance, and licensing requirements.
    - jrh206 6y ago
      Nobody's making any points about developers My gut instinct is that this is incorrect, too, but I don't know enough about surgery to make a compelling argument. I'd back myself to pick up Ruby (a language I've never touched before) and be productive, more than I'd trust a surgeon who only has experience with heart surgery to operate on my brain. Maybe that's ignorant of me.
      - mekkkkkk 6y ago
        Even if a Ruby bug would mean death? EDIT: I take this back. I missed the point of the argument.
        ceejayoz 6y ago
        That'd change the risks, sure. I don't think that's the scenario @jrh206 was talking about, though. Most code written in Ruby doesn't have the sort of immediate risk to life or limb surgeries do.
    - ceejayoz 6y ago
      Those requirements are fairly general. They don't test for "I've been doing this particularly tricky type of bone biopsy right next to the spinal cord for decades" scenarios.
    - PeterisP 6y ago
      For non-emergency surgeries it's often a long-term relationship where the same doctor who has seen the patient a few times would be the one operating - so if that particular surgeon isn't available for whatever reason, the planned operation would be rescheduled to a different date with the same doctor, not to a different doctor in the same day.
    - 6y ago
- jgtrosh 6y ago
  But the more you avoid birthday surgeries altogether, the more those that end up still happening are extreme cases with high mortality rates. So if your target is to avoid this scary statistical anomaly, you might instead want to promote more benign surgeries on birthdays.
  - mrow84 6y ago
    The types of surgeries performed should be controlled for when performing a statistical study.
    - UncleMeat 6y ago
      They were. This entire line of criticism comes from not reading the study methods.
- Operyl 6y ago
  There’s research, consultations, who is covered under what insurance, etc.
deleted 6y ago
[deleted]
newsgourmet 6y ago
I think you have it backwards. The risk of the individual surgeries is not increased. Only the risk that a surgeon will be confronted with an above average critical surgery is increased. It is not even clear that there actually is a problem. It's just a weird way to slice the data to produce an effect.
- quietbritishjim 6y ago
  > The risk of the individual surgeries is not increased. They never said that it did (unless they've edited their comment since you replied to it). They just said that the percentage [of deaths on surgeons' birthdays] will increase, and that is correct.
FabHK 6y ago
You could control for patient characteristics (age, severity of the condition, etc), and that was indeed done here, see the paper. It also specifically addresses this issue: > The major threat to the internal validity of our findings is that surgeons may selectively operate on sicker and more complex patients on their birthday, perhaps because those patients cannot have their procedures delayed. However, this is unlikely to explain our findings because we found that patients who underwent surgery on the surgeon’s birthday were similar in all observable characteristics to patients who underwent surgery on other days. Furthermore, severity of illness as measured by predicted mortality, and the number of procedures performed per surgeon, also did not differ based on whether a surgery occurred on a surgeon’s birthday compared with other days. It seems to me that the analysis is quite carefully done: > Findings were qualitatively unaffected by: using in-hospital mortality instead of 30 day mortality; additionally adjusting for the timing of the surgery; including both hospital and surgeon fixed effects in the same regression models; excluding potentially outlier surgeons with the highest mortality; using logistic regression models instead of linear probability models: using random effects models instead of fixed effects models; restricting our analysis to surgeons who performed procedures on their birthdays; additionally adjusting for the day of the year; or excluding surgeons who were born on the outlier birthdays (supplementary eTables 5-13). [...] The study findings were qualitatively unaffected when the analysis was restricted to procedures with the highest average mortality or to patients with the highest severity of illness (supplementary eTables 16 and 17).
- nkurz 6y ago
  This is a great point to raise, but it's worth noting that it directly contradicts the GP's anecdotal observation. Had they instead found greater severity on birthdays and attempted to statistically correct for it, the two would be compatible. Instead, they looked, and found that there was no underlying difference to correct for. The question then becomes whether the GP is wrong, whether the hospital in question didn't have such a policy, or whether the measurements used in the study were insufficient to pick up the difference in severity. I don't know which of these is true, but despite the apparent statistical significance of the finding, I wouldn't be confident assuming that the result is generally applicable. While not impossible, it strikes me as suspicious that they found no differences whatsoever in the surgeons' birthday vs non-birthday schedules. I somewhat wonder if by "no difference" they really meant "no statistically significant difference", which in this case wouldn't justify their lack of adjustment.

Ensorceled 6y ago

Yes, it does really mean you need to dig into actual causation or the law of unintended consequences will bite you in the ass.

faeyanpiraat 6y ago

I do not completely understand your points. Shouldn't hospitals have multiple surgeons? If one of them is on vacation, the other one does the work, and vice versa?

Galanwe 6y ago
I don't think surgeons are fongible assets. There is a lot of planning and study taking place before a complex operation. Not to mention most surgeons have specialties.
- watwut 6y ago
  The long term plans and studied for surgeries can be moved one day forward or backward basically by definition.
  - travmatt 6y ago
    Except if something changes suddenly and surgery is suddenly needed - that’s what makes it an emergency.
- daniellarusso 6y ago
  A surgeon seems more fungible than a developer, to me. All sorts of standards, compliance, and licensing requirements.
  - jrh206 6y ago
    Nobody's making any points about developers My gut instinct is that this is incorrect, too, but I don't know enough about surgery to make a compelling argument. I'd back myself to pick up Ruby (a language I've never touched before) and be productive, more than I'd trust a surgeon who only has experience with heart surgery to operate on my brain. Maybe that's ignorant of me.
    - mekkkkkk 6y ago
      Even if a Ruby bug would mean death? EDIT: I take this back. I missed the point of the argument.
      - ceejayoz 6y ago
        That'd change the risks, sure. I don't think that's the scenario @jrh206 was talking about, though. Most code written in Ruby doesn't have the sort of immediate risk to life or limb surgeries do.
  - ceejayoz 6y ago
    Those requirements are fairly general. They don't test for "I've been doing this particularly tricky type of bone biopsy right next to the spinal cord for decades" scenarios.
  - PeterisP 6y ago
    For non-emergency surgeries it's often a long-term relationship where the same doctor who has seen the patient a few times would be the one operating - so if that particular surgeon isn't available for whatever reason, the planned operation would be rescheduled to a different date with the same doctor, not to a different doctor in the same day.
  - 6y ago
jgtrosh 6y ago
But the more you avoid birthday surgeries altogether, the more those that end up still happening are extreme cases with high mortality rates. So if your target is to avoid this scary statistical anomaly, you might instead want to promote more benign surgeries on birthdays.
- mrow84 6y ago
  The types of surgeries performed should be controlled for when performing a statistical study.
  - UncleMeat 6y ago
    They were. This entire line of criticism comes from not reading the study methods.
Operyl 6y ago
There’s research, consultations, who is covered under what insurance, etc.

deleted 6y ago

[deleted]

newsgourmet 6y ago

I think you have it backwards. The risk of the individual surgeries is not increased. Only the risk that a surgeon will be confronted with an above average critical surgery is increased. It is not even clear that there actually is a problem. It's just a weird way to slice the data to produce an effect.

quietbritishjim 6y ago
> The risk of the individual surgeries is not increased. They never said that it did (unless they've edited their comment since you replied to it). They just said that the percentage [of deaths on surgeons' birthdays] will increase, and that is correct.

FabHK 6y ago

You could control for patient characteristics (age, severity of the condition, etc), and that was indeed done here, see the paper. It also specifically addresses this issue: > The major threat to the internal validity of our findings is that surgeons may selectively operate on sicker and more complex patients on their birthday, perhaps because those patients cannot have their procedures delayed. However, this is unlikely to explain our findings because we found that patients who underwent surgery on the surgeon’s birthday were similar in all observable characteristics to patients who underwent surgery on other days. Furthermore, severity of illness as measured by predicted mortality, and the number of procedures performed per surgeon, also did not differ based on whether a surgery occurred on a surgeon’s birthday compared with other days. It seems to me that the analysis is quite carefully done: > Findings were qualitatively unaffected by: using in-hospital mortality instead of 30 day mortality; additionally adjusting for the timing of the surgery; including both hospital and surgeon fixed effects in the same regression models; excluding potentially outlier surgeons with the highest mortality; using logistic regression models instead of linear probability models: using random effects models instead of fixed effects models; restricting our analysis to surgeons who performed procedures on their birthdays; additionally adjusting for the day of the year; or excluding surgeons who were born on the outlier birthdays (supplementary eTables 5-13). [...] The study findings were qualitatively unaffected when the analysis was restricted to procedures with the highest average mortality or to patients with the highest severity of illness (supplementary eTables 16 and 17).

nkurz 6y ago
This is a great point to raise, but it's worth noting that it directly contradicts the GP's anecdotal observation. Had they instead found greater severity on birthdays and attempted to statistically correct for it, the two would be compatible. Instead, they looked, and found that there was no underlying difference to correct for. The question then becomes whether the GP is wrong, whether the hospital in question didn't have such a policy, or whether the measurements used in the study were insufficient to pick up the difference in severity. I don't know which of these is true, but despite the apparent statistical significance of the finding, I wouldn't be confident assuming that the result is generally applicable. While not impossible, it strikes me as suspicious that they found no differences whatsoever in the surgeons' birthday vs non-birthday schedules. I somewhat wonder if by "no difference" they really meant "no statistically significant difference", which in this case wouldn't justify their lack of adjustment.