In the past, epidemiologists derived conclusions from large data sets, whereas clinicians analyzed smaller series of individually characterized cases. Increasingly, clinicians attempt to derive conclusions from large sets of variably defined data; the conclusions may be erroneous.
A case in point is the recent report of 1669 patients hospitalized for “community-acquired pneumonia.”1 The authors found that gram stain and culture of sputum were useful in only 14% of patients. The accompanying editorial regarded these microbiologic techniques as a sacred cow that should be sent out to pasture.2
Musher DM. The Usefulness of Sputum Gram Stain and Culture. Arch Intern Med. 2005;165(4):470–471. doi:10.1001/archinte.165.4.470-b