On Mon, 8 Nov 2004 11:01:43 -0600, Dan Minette <[EMAIL PROTECTED]> wrote:
> The selection was not random. The initial selection was. But, the > investigators could not go everywhere. Thus, they chose neighborhoods that > "looked the same." This substitution was subjective and not random. Thus, > a bias was built into the methodology. A rebuttal of this view: 1) It is not true that they could not visit some clusters because the roads were blocked off. 2) They did not pick other more accessible regions. To reduce travel, they paired governorates with similar violence levels and move all the clusters in the pair into one of the governorates. 3) It was not unclear how they did this calculation since the report explains it in excruciating detail. 4) The moving was clusters was randomized so that it did not destroy the survey's randomness. 5) It is not true that they expanded the survey to an adjoining clusters if there weren't enough people in a cluster. The sampling unit was households, not people. And a cluster was the thirty households that were nearest a randomly chosen location. http://cgi.cse.unsw.edu.au/~lambert/cgi-bin/blog/2004/11#lancet7 Martin _______________________________________________ http://www.mccmedia.com/mailman/listinfo/brin-l
