PMID: 11914308Mar 27, 2002Paper

Number and size of randomized trials reported in general health care journals from 1948 to 1997

International Journal of Epidemiology
Steve McDonaldCochrane Centres' Working Group on 50 Years of Randomized Trials

Abstract

Randomized trials are important for controlling selection biases, and where sufficient numbers of participants are involved, have the potential to yield reliable estimates of treatment effects. We investigated trends in the number and size of randomized trials reported in general health care journals from 1948 to 1997. From the handsearching of 18 general health care journals we collected data on the number of reports of randomized trials in each journal per year, and the number of participants in each trial. A total of 5503 reports of trials were identified in 18 general health care journals. More than a third appeared in the British Medical Journal. The peak period for trial reports was the mid 1980s, with more in 1986 than any other year (242). By the mid 1990s the number per year had declined by a third. Trials with fewer than 100 participants accounted for most of the reports (69%). In spite of the overall decline in the number of trial reports, those involving 100 participants or more continued to increase throughout the period studied. The continued increase in the number of larger trials reported is encouraging, especially if it represents an increase in the size of trials more generally. Further research is needed to d...Continue Reading

References

Dec 27, 1995·JAMA : the Journal of the American Medical Association·L Bero, D Rennie
Oct 31, 1998·BMJ : British Medical Journal·B Thornley, C Adams
Oct 31, 1998·BMJ : British Medical Journal·R Doll

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Citations

Mar 23, 2011·Journal of Gastroenterology and Hepatology·Sarah Louise KlingenbergChristian Gluud
Apr 6, 2011·BMJ Quality & Safety·Frank Davidoff
Jun 2, 2012·Journal of Pain and Symptom Management·Jane L WheelerDavid C Currow
Oct 6, 2004·Allergy·Barbara CaraccioloSergio Bonini
Nov 8, 2005·Journal of Cystic Fibrosis : Official Journal of the European Cystic Fibrosis Society·Tracy Ann BriggsRosalind L Smyth
Jul 27, 2007·Revista latino-americana de enfermagem·Cristina Mamédio da Costa SantosMoacyr Roberto Cuce Nobre
Mar 27, 2002·International Journal of Epidemiology·Matthias EggerGeorge Davey Smith
Nov 11, 2005·Clinical Trials : Journal of the Society for Clinical Trials·Sally Hopewell, Mike Clarke
Jan 31, 2006·American Journal of Epidemiology·Lise Lotte Gluud
Jun 2, 2011·Spine·Peter CroftMaurits van Tulder

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