A reduction in error rate of 400-600%: Pretty good, huh?

In comments to the previous post, Alexey Guzey points to this bit from his post on sleep legend Matthew Walker:

In The Lancet, Walker writes:

pilot studies have shown that when you limit trainee doctors to no more than a 16 h shift, with at least an 8 h rest opportunity before the next shift, serious medical errors drop by over 20%. Furthermore, residents make 400–600% fewer diagnostic errors to begin with.

In Neuron, Walker writes:

pilot studies have shown that when you limit trainee doctors to no more than a 16-h shift, with at least an 8-h rest opportunity before the next shift, serious medical errors drop by over 20%. Furthermore, residents make 400%–600% fewer diagnostic errors to begin with (Walker, 2017).

And in Why We Sleep, Walker writes:

several pilot studies in the US have shown that when you limit residents to no more than a sixteen-hour shift, with at least an eight-hour rest opportunity before the next shift, the number of serious medical errors made—defined as causing or having the potential to cause harm to a patient—drops by over 20 percent. Furthermore, residents made 400 to 600 percent fewer diagnostic errors to begin with.

A reduction of 400-600%? 400-600%??? As Guzey notes, you can’t reduce the number (or rate) of errors by more than 100%.

This is Wansink or Wegman-level sloppiness here.

A good reminder, I suppose, that peer review is literally nothing more than review by peers. And of course we can expect your peers to make exactly the same mistakes that you do. They’re your peers, after all! It’s a good thing we have some non-peers around to check things out from time to time.

P.S. Ha ha, you might say, very amusing but this must just be some silly typo or miscalculation; you can’t judge an entire book based on one silly mistake. Then again:

1. It seems that this book had lots and lots of silly mistakes, to the extent that it’s not clear what we’re supposed to believe from it.

2. It’s not clear what the statement was supposed to be. I’m guessing 40-60%: but if that’s really what happened, it would be good to see the data backing it up, and it doesn’t seem that there is any data backing it up.

3. For this same error to appear three different times . . . aren’t the authors reading their own papers? I mean, sure, I too have published embarrassing stuff under my name. But at least I don’t make the identical mistake three times. To paraphrase Oscar Wilde: to make a mistake once may be regarded as a misfortune; to do it thrice looks like carelessness.