If you follow some of the links you can get the original article,
http://medicine.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pmed.0030487.
Which if you read is a self reported/self control study done only on interns, and was done in the
02-03 academic year, when hardly anyone was 80h compliant. They were basically asked if they thought they made mistakes due to sleep deprivation, which is huge recall bias, and also, who wouldnt want to place some blame on sleepiness instead of the law of averages or just screwing up? Terrible study, someone needs to blow that thing to shreds, before they allow it to ruin medicine. Falling asleep in lecture really has nothing to do with patient care. Also, it shows the difference in sleep per month to be 14h from a good month to a terrible month. Doesnt seem that big a number to make any difference.
Also, although interns may feel that they were the ones responsible for a certain error or problem, rarely is it actually squarely their fault, thats the point of residency, graduated responsibility. Seems they have taken advantage of the martyr attitude most drs have to use it for bad science.