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os seguintes textos:
Case-control
studies of antenatal drug exposure and birth defects often rely on maternal
recall of drug use in pregnancy. Differential recall among mothers of cases
and controls can lead to information bias ("maternal recall bias"), and the
opportunity for such bias increases as ascertainment of drug exposure diminishes.
The effect of questionnaire design on the ascertainment of drug use in
pregnancy was examined in two studies. In a pilot interview study of 532 women
in Obstetric/gynecologic practices, information on drug use in the past
year was obtained by means of three questions asked in sequence: The first question
was open-ended, the second asked about drug use for selected indications, and
the third asked about use of specifically named drugs. Among obstetric patients
who reported use of any of five drugs, less than 50% did so in response to the
open-ended question, and approximately 20-40% reported use only when the specific
drug name was asked. In a case-control Birth Defects Study of 5,435 mothers
of malformed children, information on drug use in pregnancy was obtained by
asking questions in sequence about indications and specifically named drugs.
Among the women who reported use of any of 11 drugs, 6-40% did so only when
asked about the specific drug by name. These findings suggest that completeness
of ascertainment of antenatal drug exposure varies according to how the mother
is questioned and is directly related to the specificity of the questions asked.
(Effect of questionnaire design on recall of drug exposure in pregnancy.
Mitchell AA, Cottler LB, Shapiro S. Am J Epidemiol 1986 Apr;123(4):670-6)
"The first
persons in whom the cytomegalovirus infection was diagnosed were those with
severe disease, this virus was initially thought to be highly virulent. As more
people were tested for the virus, it became clear that the virus is widespread
and only rarely leads to serious illness."
(Biomedical Bestiary. Michael III, Max; W. Thomas Boyce, Allen J. Wilcox;
Little, Brown and Company. 1984.)
1. O primeiro texto mostra como o tipo de questão (aberta ou fechada) influência a resposta. Que vantagens e desvantagens tem o uso de questões de resposta aberta?
2. Qual a razão da conclusão errada tirada inicialmente no estudo descrito no segundo texto?