Background. Existing fetal growth references all suffer from 1 or more major methodologic
problems, including errors in reported gestational age, biologically implausible birth weight for …

Overadjustment is defined inconsistently. This term is meant to describe control (eg, by
regression adjustment, stratification, or restriction) for a variable that either increases net bias or …

Context The evidence that breastfeeding improves cognitive development is based almost
entirely on observational studies and is thus prone to confounding by subtle behavioral …

The objective of most biomedical research is to determine an unbiased estimate of effect for
an exposure on an outcome, ie to make causal inferences about the exposure. Recent …

ContextThe World Health Organization defines preterm birth as birth at less than 37 completed
gestational weeks, but most studies have focused on very preterm infants (birth at <32 …

That conditioning on a common effect of exposure and outcome may cause selection, or
collider-stratification, bias is not intuitive. We provide two hypothetical examples to convey …

Some authors argue that systematic reviews and meta-analyses of intervention studies
should include only randomized controlled trials because the randomized controlled trial is a …

Background: The evidence that breastfeeding protects against obesity and a variety of chronic
diseases comes almost entirely from observational studies, which have a potential for bias …

Background: Opinions and recommendations about the optimal duration of exclusive breastfeeding
have been strongly divided, but few published studies have provided direct evidence …

OBJECTIVES: To determine whether prevalent delirium is an independent predictor of
mortality in older patients seen in emergency departments (EDs) and discharged home without …