Selection bias: neighbourhood controls and controls selected from those presenting to a Health Unit in a case control study of efficacy of BCG revaccination
<p>Abstract</p> <p>Background</p> <p>In most case control studies the hardest decision is the choice of the control group, as in the ideal control group the proportion exposed is the same as in the population that produced the cases.</p> <p>Methods</p>...
Main Authors: | , , , , , , |
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Format: | Article |
Language: | English |
Published: |
BMC
2007-02-01
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Series: | BMC Medical Research Methodology |
Online Access: | http://www.biomedcentral.com/1471-2288/7/11 |