%0 Journal Article %T A controlled trial of the effectiveness of internet continuing medical education %A Linda Casebeer %A Sally Engler %A Nancy Bennett %A Martin Irvine %A Destry Sulkes %A Marc DesLauriers %A Sijian Zhang %J BMC Medicine %D 2008 %I BioMed Central %R 10.1186/1741-7015-6-37 %X To determine the effectiveness of a group of 48 internet continuing medical education (CME) activities, case vignette surveys were administered to US physicians immediately following participation, and to a representative control group of non-participant physicians. Responses to case vignettes were analyzed based on evidence presented in the content of CME activities. An effect size for each activity was calculated using Cohen's d to determine the amount of difference between the two groups in the likelihood of making evidence-based clinical decisions, expressed as the percentage of non-overlap, between the two groups. Two formats were compared.In a sample of 5621 US physicians, of the more than 100,000 physicians who participated in 48 internet CME activities, the average effect size was 0.75, an increased likelihood of 45% that participants were making choices in response to clinical case vignettes based on clinical evidence. This likelihood was higher in interactive case-based activities, 51% (effect size 0.89), than for text-based clinical updates, 40% (effect size 0.63). Effectiveness was also higher among primary care physicians than specialists.Physicians who participated in selected internet CME activities were more likely to make evidence-based clinical choices than non-participants in response to clinical case vignettes. Internet CME activities show promise in offering a searchable, credible, available on-demand, high-impact source of CME for physicians.The internet has had a strong impact on how physicians access information, and many have reported the influence of this information on their medical decision making [1,2]. The internet offers a platform for addressing healthcare quality and patient safety by assisting with diagnosis and patient management, and facilitating the free flow of information [3]. The internet also offers opportunities to facilitate improvement in the quality of care through physician maintenance of certification [4,5].Rapid growth %U http://www.biomedcentral.com/1741-7015/6/37