One alternative to the assumption of no unmeasured
confounding is to identify an instrument.
In particular, we focus on
confounding by variables that are unknown or unmeasured, which pose a special threat because the inclusion of multiple exposure variables together in a model can sometimes--depending on the causal structure--make things worse, amplifying the amount of bias in a regression estimate compared with analyzing single exposures.
This may impact the estimation of effect size due to postrandomization
confounding.
Residual
confounding can exist in an observational study due to known confounders, which were not measured, or unknown confounders, which are not apparent to even the most astute of reviewers.
The researcher intended to combine the data sets from the two semesters, but needed to be mindful of the potential for
confounding or lurking variables.
The relationship between breast-feeding and subsequent child health outcomes may also be subject to time-dependent
confounding, when risk factors for the outcome both predict and are changed by breast-feeding.
The study from Nationwide Children's Hospital is the first to use methods controlling for the widest range of
confounding factors when directly examining the association between gestational weight gain and childhood cognition.
Confounding variables studied included female age, duration of infertility, cause of infertility, smoking status, ovarian reserve, history of previous miscarriage, method of oocyte fertilisation and grade of blastocyst transferred.
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He pointed out that visit of President Asif Ali Zardari to Punjab has perplexed PML-N leadership and that's the reason they were airing
confounding statements adding that PML-N should realized it that President Asif Ali Zardari was elected President of the country and he can visit in any part of the country and it should be responsibility of PML-N Punjab Government to welcome the Presidency in Punjab.
1 BIRMINGHAM manager Alex McLeish believes Lee Bowyer is
confounding his critics after he was again the goal hero in the victory over Wolves at Molineux.
In other words, adults at highest risk for type 2 diabetes had the lowest birth weights, independent of potentially
confounding factors such as body size and socioeconomic status in adulthood, wrote Peter H.
Welles was frequently forced to act in routine films to finance his film-making activities but throughout his career he was always capable of
confounding the sceptics with more evidence of his unflagging talent.
