Library / Contradicted and Initially Stronger Effects in Highly Cited Clinical Research

Reference

John PA Ioannidis “Contradicted and Initially Stronger Effects in Highly Cited Clinical Research” (2005) // JAMA. Publisher: American Medical Association (AMA). Vol. 294. No 2. Pp. 218. DOI: 10.1001/jama.294.2.218

Bib

@Article{ioannidis2005a,
  title = {Contradicted and Initially Stronger Effects in Highly Cited Clinical Research},
  volume = {294},
  issn = {0098-7484},
  url = {http://dx.doi.org/10.1001/jama.294.2.218},
  doi = {10.1001/jama.294.2.218},
  number = {2},
  journal = {JAMA},
  publisher = {American Medical Association (AMA)},
  author = {Ioannidis, John PA},
  year = {2005},
  month = {jul},
  pages = {218}
}

Quotes (1)

Evaluating the Reliability of Highly Cited Clinical Research Studies

Of 49 highly cited original clinical research studies, 45 claimed that the intervention was effective. Of these, 7 (16%) were contradicted by subsequent studies, 7 others (16%) had found effects that were stronger than those of subsequent studies, 20 (44%) were replicated, and 11 (24%) remained largely unchallenged. Five of 6 highlycited nonrandomized studies had been contradicted or had found stronger effects vs 9 of 39 randomized controlled trials (P=.008). Among randomized trials, studies with contradicted or stronger effects were smaller (P=.009) than replicated or unchallenged studies although there was no statistically significant difference in their early or overall citation impact. Matched control studies did not have a significantly different share of refuted results than highly cited studies, but they included more studies with “negative” results.