Interesting article: How Quickly Do Systematic Reviews Go Out of Date? A Survival Analysis. Kaveh G. Shojania, Margaret Sampson, Mohammed T. Ansari, Jun Ji, Steve Doucette, and David Moher. Annals of Internal Medicine (2007, Aug 21), 147(4): 224-233. [Abstract] [Full text] [PDF] Description: Systematic reviews summarize all the data up to a certain time, so they can become "stale" over time. The authors selected a sample of systematic reviews and noted how often a new review of the same topic presented a change in statistical significance or a large change in the estimated magnitude of the effect. Using classic measures in survival analysis, the authors estimated half of the studies did not see such a shift until 5.5 years, but a significant fraction saw such a signal after one or two years. The description of this article was written on 2007-08-27, 2008-01-12. Category: Interesting articles, Category: Systematic overviews