What is a confounding effect?
Confounding is often referred to as a “mixing of effects”1,2 wherein the effects of the exposure under study on a given outcome are mixed in with the effects of an additional factor (or set of factors) resulting in a distortion of the true relationship.
What is confounder in statistics?
A Confounder is an extraneous variable whose presence affects the variables being studied so that the results do not reflect the actual relationship between the variables under study.
How does confounding affect results?
Confounding factors, if not controlled for, cause bias in the estimate of the impact of the exposure being studied. The effects of confounding can result in: * An observed difference between study populations when no real difference exists.
What is the difference between covariates and confounders?
Confounding occurs when there is a relation between a certain characteristic or covariate (C) and group allocation (G) and also between this characteristic and the outcome (O). When the occurs the covariate (C) is termed a confounder. Whereas: Mediators are part of the causal pathway from exposure to outcome.
Can confounding cause bias?
Confounding is also a form a bias. Confounding is a bias because it can result in a distortion in the measure of association between an exposure and health outcome.
Why is confounding a problem?
A confounding variable is a third variable that influences both the independent and dependent variables. Failing to account for confounding variables can cause you to wrongly estimate the relationship between your independent and dependent variables.
Are all covariates confounders?
Covariates are other independent variables that may or may not predict outcomes. A covariate may or may not be confounder.
What are sources of confounding?
Confounding variables (a.k.a. confounders or confounding factors) are a type of extraneous variable that are related to a study’s independent and dependent variables. A variable must meet two conditions to be a confounder: It must be correlated with the independent variable.