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>...

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Bibliographic Details
Main Authors: de Souza Wayner V, Montarroyos Ulisses R, de Albuquerque Maria, Ximenes Ricardo AA, Dantas Odimariles MS, Varejão Patrícia, Rodrigues Laura C
Format: Article
Language:English
Published: BMC 2007-02-01
Series:BMC Medical Research Methodology
Online Access:http://www.biomedcentral.com/1471-2288/7/11