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. Author manuscript; available in PMC: 2012 Nov 10.
Published in final edited form as: Clin Trials. 2009 Apr;6(2):141–150. doi: 10.1177/1740774509102590

Figure 5.

Figure 5

Annual critical variable error rates, 1999–2006. Critical variable error rates generally declined in tandem with total database error rates. The exception observed for 2000 (in which critical variable rate exceeded overall error rate) may be attributable to variation in trial methodologies and aims.