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One of my pet hates is that I have not been able to crack how to make doctors talk about probabilities quantitatively. It just seems to be impossible. So far I

One of my pet hates is that I have not been able to crack how to make doctors talk about probabilities quantitatively. It just seems to be impossible. So far I have three theories why this is: 1. Med school teaches people that as they are just a little above God, they are always correct and do not need to care about probabilites. 2. MD's just do not understand probability and it is not taught in med school 3. Most patients have no clue about probability, can't stand uncertainty and they just want "the truth" from the doctor, who then calibrate their behavior according to that. I kind of hope it is 3. but occasionally feel like it is 1 or 2.

opo 7y ago
>...I kind of hope it is 3. but occasionally feel like it is 1 or 2. Unfortunately #2 appears to be an issue for many doctors: https://blogs.cornell.edu/info2040/2014/11/12/doctors-dont-know-bayes-theorem/ https://blogs.cornell.edu/info2040/2014/11/12/doctors-dont-k...
ForHackernews 7y ago
I read When Breath Becomes Air, [0] the story of a physician-scientist's own battle with cancer, and one of the things he writes about was his frustration at getting treated like a patient when he was trying to get hard numbers for his survival probabilities. It seems the consensus in the medical community is that there's very little good that can come from giving odds to a patient. What are you going to do with that information? [0] https://www.goodreads.com/book/show/30241171-when-breath-becomes-air https://www.goodreads.com/book/show/30241171-when-breath-bec...
- beefield 7y ago
  > What are you going to do with that information? Yep. Why on earth should I be given the means to make informed decisions about my body and life? What an outrageous idea. (sarcasm included)
- perl4ever 7y ago
  It's a very memorable experience when a doctor thinks he is helping by telling a person they are recovering from a terminal illness and they and their loved ones take him at his word and then go nuts trying to figure out why symptoms are getting worse. That's the slippery slope you end up on when you say odds don't matter.
Engineering-MD 7y ago
Or none of the above. So, you can apply statistics to medicine in the form of incidence of a disease, and likelihood ratios to increase or decrease the chance of disease in diagnosis. The problem is, the data for these is so difficult to interpret. Likelihood ratios in papers often have huge confidence intervals (like anywhere from 2-15), making their use problematic. Then often, they are quoted only for very specific patient groups, and applying them out of these groups invalidates the rule. Then things like prognosis are so variable, taking quantitively becomes a bit pointless. It’s especially true in cases where treatment or investigations are changing constantly, such as cancer. For diagnosis, the history is often more useful. Humans are story tellers, and the description of the problem varies hugely between patients, as does the significance of certain symptoms or descriptions. It’s an art to work out what is the real symptom and what isn’t. To work out the real picture isn’t always easy either. Ultimately for things where there is relatively good evidence to practice statistics they are made into algorithms (see MDCalc for examples) but again it’s hard to apply them out of the correct patient population. Even these rules seem to poorly apply in many situations. Then, real hard statistics rarely change management. You think of the reasonable causes and risk reduce as far as possible. Knowing the actual probability doesn’t really change what you can do. Same kind of goes for prognosis. Most patients don’t really know what to do with exact numbers (especially when they vary so much between different patients). So, ultimately this is why doctors don’t use statistics regularly.
- beefield 7y ago
  Sorry, but that is to me a textbook example of what I think as case 2. It is not about hard statistics. It is your job to translate all those uncertainties and sources of knowledge to (subjective) probabilities. If you do not do that, you are doing things wrong. I do not see how there is anything to even discuss here. Probabilities are the current best tool we have to work with uncertainties. I do not hire a doctor to just tell me what will be done. I hire a doctor as a consultant to give advice what he thinks is wise given his knowledge and then I do the decision what I do with my body and life. And the consultant should damn well give the best available information he has, just not think that I am so dumb that I can't decide myself.[1] (Again, sorry for the rant, I have been way too frustrated on this specific issue earlier in my life) [1] Obviously, most of the time I do agree with doctor's recommendations. But if I am one day having a cancer and a doctor refuses to estimate the odds for me living another month, year and decade, strong verbal abuse is given.

opo 7y ago

>...I kind of hope it is 3. but occasionally feel like it is 1 or 2. Unfortunately #2 appears to be an issue for many doctors: https://blogs.cornell.edu/info2040/2014/11/12/doctors-dont-know-bayes-theorem/ https://blogs.cornell.edu/info2040/2014/11/12/doctors-dont-k...

ForHackernews 7y ago

I read When Breath Becomes Air, [0] the story of a physician-scientist's own battle with cancer, and one of the things he writes about was his frustration at getting treated like a patient when he was trying to get hard numbers for his survival probabilities. It seems the consensus in the medical community is that there's very little good that can come from giving odds to a patient. What are you going to do with that information? [0] https://www.goodreads.com/book/show/30241171-when-breath-becomes-air https://www.goodreads.com/book/show/30241171-when-breath-bec...

beefield 7y ago
> What are you going to do with that information? Yep. Why on earth should I be given the means to make informed decisions about my body and life? What an outrageous idea. (sarcasm included)
perl4ever 7y ago
It's a very memorable experience when a doctor thinks he is helping by telling a person they are recovering from a terminal illness and they and their loved ones take him at his word and then go nuts trying to figure out why symptoms are getting worse. That's the slippery slope you end up on when you say odds don't matter.

Engineering-MD 7y ago

Or none of the above. So, you can apply statistics to medicine in the form of incidence of a disease, and likelihood ratios to increase or decrease the chance of disease in diagnosis. The problem is, the data for these is so difficult to interpret. Likelihood ratios in papers often have huge confidence intervals (like anywhere from 2-15), making their use problematic. Then often, they are quoted only for very specific patient groups, and applying them out of these groups invalidates the rule. Then things like prognosis are so variable, taking quantitively becomes a bit pointless. It’s especially true in cases where treatment or investigations are changing constantly, such as cancer. For diagnosis, the history is often more useful. Humans are story tellers, and the description of the problem varies hugely between patients, as does the significance of certain symptoms or descriptions. It’s an art to work out what is the real symptom and what isn’t. To work out the real picture isn’t always easy either. Ultimately for things where there is relatively good evidence to practice statistics they are made into algorithms (see MDCalc for examples) but again it’s hard to apply them out of the correct patient population. Even these rules seem to poorly apply in many situations. Then, real hard statistics rarely change management. You think of the reasonable causes and risk reduce as far as possible. Knowing the actual probability doesn’t really change what you can do. Same kind of goes for prognosis. Most patients don’t really know what to do with exact numbers (especially when they vary so much between different patients). So, ultimately this is why doctors don’t use statistics regularly.

beefield 7y ago
Sorry, but that is to me a textbook example of what I think as case 2. It is not about hard statistics. It is your job to translate all those uncertainties and sources of knowledge to (subjective) probabilities. If you do not do that, you are doing things wrong. I do not see how there is anything to even discuss here. Probabilities are the current best tool we have to work with uncertainties. I do not hire a doctor to just tell me what will be done. I hire a doctor as a consultant to give advice what he thinks is wise given his knowledge and then I do the decision what I do with my body and life. And the consultant should damn well give the best available information he has, just not think that I am so dumb that I can't decide myself.[1] (Again, sorry for the rant, I have been way too frustrated on this specific issue earlier in my life) [1] Obviously, most of the time I do agree with doctor's recommendations. But if I am one day having a cancer and a doctor refuses to estimate the odds for me living another month, year and decade, strong verbal abuse is given.