BMJ 2001;322:879-880 ( 14 April )

Editorials

Any casualties in the clash of randomised and observational evidence?

Norecent comparisons have studied selected questions, but we do need more data

The first 150 words of the full text of this article appear below.

Randomised controlled trials and observational studies are often seen as mutually exclusive, if not opposing, methods of clinical research. Two recent reports, however, identified clinical questions (19 in one report,¹ five in the other²) where both randomised trials and observational methods had been used to evaluate the same question, and performed a head to head comparison of them. In contrast to the belief that randomised controlled trials are more reliable estimators of how much a treatment works, both reports found that observational studies did not overestimate the size of the treatment effect compared with their randomised counterparts. The authors say that the merits of well designed observational studies may need to be re-evaluated: case-control and cohort studies may need to assume more respect in assessing medical therapies and largescale observational databases should be better exploited. ^{1 2} The first claim flies in the face of half a century of thinking, so are . . . [Full text of this article]

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    StumbleUpon    Technorati    What's this?

Relevant Articles

Use of primary care electronic medical record database in drug efficacy research on cardiovascular outcomes: comparison of database and randomised controlled trial findings

Richard L Tannen, Mark G Weiner, and Dawei Xie
BMJ 2009 338: b81. [Abstract] [Full Text] [PDF]

Effectiveness of antipsychotic treatments in a nationwide cohort of patients in community care after first hospitalisation due to schizophrenia and schizoaffective disorder: observational follow-up study

Jari Tiihonen, Kristian Walhbeck, Jouko Lönnqvist, Timo Klaukka, John P A Ioannidis, Jan Volavka, and Jari Haukka
BMJ 2006 333: 224. [Abstract] [Full Text] [PDF]

This article has been cited by other articles:

• Tannen, R. L, Weiner, M. G, Xie, D. (2009). Use of primary care electronic medical record database in drug efficacy research on cardiovascular outcomes: comparison of database and randomised controlled trial findings. BMJ 338: b81-b81 [Abstract] [Full text]  
• Tatsioni, A., Bonitsis, N. G., Ioannidis, J. P. A. (2007). Persistence of Contradicted Claims in the Literature. JAMA 298: 2517-2526 [Abstract] [Full text]  
• Tiihonen, J., Walhbeck, K., Lonnqvist, J., Klaukka, T., Ioannidis, J. P A, Volavka, J., Haukka, J. (2006). Effectiveness of antipsychotic treatments in a nationwide cohort of patients in community care after first hospitalisation due to schizophrenia and schizoaffective disorder: observational follow-up study. BMJ 333: 224- [Abstract] [Full text]  
• Papanikolaou, P. N., Christidi, G. D., Ioannidis, J. P.A. (2006). Comparison of evidence on harms of medical interventions in randomized and nonrandomized studies. CMAJ 174: 635-641 [Abstract] [Full text]  
• Lee, J.Y., Rozier, R.G., Norton, E.C., Vann, W.F. Jr. (2005). Addressing Selection Bias in Dental Health Services Research. JDR 84: 942-946 [Abstract] [Full text]  
• Patsopoulos, N. A., Analatos, A. A., Ioannidis, J. P. A. (2005). Relative Citation Impact of Various Study Designs in the Health Sciences. JAMA 293: 2362-2366 [Abstract] [Full text]  
• Tooth, L., Ware, R., Bain, C., Purdie, D. M., Dobson, A. (2005). Quality of Reporting of Observational Longitudinal Research. Am J Epidemiol 161: 280-288 [Abstract] [Full text]  
• Silliman, R. A. (2003). What Constitutes Optimal Care for Older Women With Breast Cancer?. JCO 21: 3554-3556 [Full text]  
• Katsifis, G. E., Tzioufas, A. G., Vlachoyiannopoulos, P. G., Voulgarelis, M., Moutsopoulos, H. M., Ioannidis, J. P. A. (2002). Risk of myelotoxicity with intravenous cyclophosphamide in patients with systemic lupus erythematosus. Rheumatology (Oxford) 41: 780-786 [Abstract] [Full text]  
• Rychetnik, L, Frommer, M, Hawe, P, Shiell, A (2002). Criteria for evaluating evidence on public health interventions. J. Epidemiol. Community Health 56: 119-127 [Abstract] [Full text]  
• Laheij, R. J. F., Theodoropoulos, D. S., Theodoropoulos, G. A., Pecoraro, D. L., Ioannidis, J. P. A., Contopoulos-Ioannidis, D. G., Lau, J. (2001). Using Meta-analysis to Answer Clinical Questions. JAMA 286: 2669-2670 [Full text]  
• Ioannidis, J. P. A., Haidich, A.-B., Pappa, M., Pantazis, N., Kokori, S. I., Tektonidou, M. G., Contopoulos-Ioannidis, D. G., Lau, J. (2001). Comparison of Evidence of Treatment Effects in Randomized and Nonrandomized Studies. JAMA 286: 821-830 [Abstract] [Full text]  

Rapid Responses:

Read all Rapid Responses

Random variability or bias?

Chris Gale
bmj.com, 18 Apr 2001 [Full text]

Re: Random variability or bias?

John P A Ioannidis
bmj.com, 23 Apr 2001 [Full text]

Randomized and observational evidence: time for a change in the paradigm?

Jose Antonio Sacristán
bmj.com, 26 Apr 2001 [Full text]

Not All Clinical Trials Are Created Equal

Vance W Berger
bmj.com, 28 Apr 2001 [Full text]

Online poll

Find out more >>