21.   Moreover, when things go well, no one pays attention, but when a mistake occurs, everyone notices.

22.   Mistakes do occur. . . .

23.   Mistakes will occur, sometimes dependent upon your ability to explain and train.

24.   NASA and Lockheed officials said the full details of how the mistake occurred are not known.

25.   NASA and Lockheed officials said the full details of how the mistake occurred were not known.

26.   Of course, when mistakes do occur, they can lower -- for a lifetime -- the amount received by the unlucky retiree, surviving spouse or family.

27.   One nurse was specifically assigned to spot the problem cases and try to make sure that a similar mistake did not occur again.

28.   Police sources who would speak only if they were guaranteed confidentiality said they did not believe such mistakes occurred frequently.

29.   The mistake occurred through a miscalculation of the percentile score that showed how the students compared to a national sample of children across the country.

30.   The officials said they do not think that ACOG is cutting corners or is working so quickly that mistakes are occurring.