Comparison of evidence on harms of medical interventions in randomized and nonrandomized studies
Canadian Medical Association JournalPublished 27 February 2006Open access
Panagiotis N. Papanikolaou
Citations230
SJR quartileQ1
SJR score0.92
SNIP1.00
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TL;DR
Evidence from randomized trials is compared with that from epidemiologic studies to determine whether they give different estimates of risk for important harms of medical interventions, and nonrandomized studies are often conservative in estimating absolute risks of harms.
Abstract
Nonrandomized studies are often conservative in estimating absolute risks of harms. It would be useful to compare and scrutinize the evidence on harms obtained from both randomized and nonrandomized studies.
Keywords
Decision SciencesEconomics, Econometrics and FinancePharmacology, Toxicology and Pharmaceutics
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