I still donât think youâre wrong. Will is correct when he says that it is more likely someone with a BMI of 25 or lower is actually overweight than someone with a BMI of 25 or higher is just well-muscled, but that isnât the same as estimating by eye.
The point, as I understand it, is that if you live in a country where most people are overweight, your understanding of what âoverweightâ is will naturally be skewed. If the average person in your home country has a BMI of 25-30, youâll see that subconsciously as normal, and therefore you could see plenty of mildly overweight people and not think they were overweight at allâonly people at even higher BMIâs would be identifiable as overweight to you.
Will is correct when he says âIt is more likely someone with a BMI of 25 or lower is actually overweight than someone with a BMI of 25 or higher is just well-muscledâ, but that isnât the same as estimating by eye.
Relatively minor in this particular case, but: Please donât claim people said things they didnât actually say. I know youâre paraphrasing, but to me the combination of âwhen he saysâ with quote marks strongly implies a verbatim quote. Itâs pretty important to clearly distinguish between those two things.
I agree âBMI gives lots of false negatives compared to more reliable measures of overweightâ is not the same thing as âBMI is more prone to false negatives than by-eye estimationâ â it could be that BMI underestimates overweight, but by-eye estimation underestimates it even more. It would be great to see a study comparing both BMI and by-eye estimation to a third metric (I havenât searched for this).
But if BMI is more prone to false negatives, and less prone to false positives, than most people think, that still seems to me like prima facie evidence against the claim that the opposite (that by-eye will underestimate relative to BMI) is true.
I still donât think youâre wrong. Will is correct when he says that it is more likely someone with a BMI of 25 or lower is actually overweight than someone with a BMI of 25 or higher is just well-muscled, but that isnât the same as estimating by eye.
The point, as I understand it, is that if you live in a country where most people are overweight, your understanding of what âoverweightâ is will naturally be skewed. If the average person in your home country has a BMI of 25-30, youâll see that subconsciously as normal, and therefore you could see plenty of mildly overweight people and not think they were overweight at allâonly people at even higher BMIâs would be identifiable as overweight to you.
Relatively minor in this particular case, but: Please donât claim people said things they didnât actually say. I know youâre paraphrasing, but to me the combination of âwhen he saysâ with quote marks strongly implies a verbatim quote. Itâs pretty important to clearly distinguish between those two things.
Fair enough. Iâve edited it to remove the quotation marks.
I agree âBMI gives lots of false negatives compared to more reliable measures of overweightâ is not the same thing as âBMI is more prone to false negatives than by-eye estimationâ â it could be that BMI underestimates overweight, but by-eye estimation underestimates it even more. It would be great to see a study comparing both BMI and by-eye estimation to a third metric (I havenât searched for this).
But if BMI is more prone to false negatives, and less prone to false positives, than most people think, that still seems to me like prima facie evidence against the claim that the opposite (that by-eye will underestimate relative to BMI) is true.