This is a line graph showing a plot of the number of publications using the terms "randomi* in clusters" or "cluster randomi*" against year, for the years 1980-2001.
Three lines are shown: all papers, trials, and methods. There are similar numbers of trial reports and methods papers in each year. There is a rapid rise in all three lines since 1997. The first four papers were all be by Donner and colleagues.
Numbers for 2001 were estimated for the first six months.
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This page maintained by Martin Bland.
Last updated: April 5, 2004.