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    Hi,

    Can someone explain the difference between an extraneous and confounding variable?

    Thanks.
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    (Original post by DianaJones)
    Hi,

    Can someone explain the difference between an extraneous and confounding variable?

    Thanks.
    Hmm, i thought they were different but looked up the definitions in the Oxford Psychology Dictionary and they seem to be the same.

    I mostly read "extraneous variables" in the context of observational studies where one is examining factors that potentially influence correlations between variables. In contrast, confounding variable seems to be used much more often in relation to experimental designs, and refers to a factor that differs between the control and experimental group, because the researchers failed to account for it.

    Extraneous Variable: "In statistics and research design, a variable that is of no immediate interest to a researcher but is capable of influencing variables that are of interest. In experimental design, such an extraneous variable is capable of influencing the dependent variable, and it is normally controlled by randomization; when it cannot be controlled, efforts are often made to measure and allow for it. Also called a nuisance variable."

    Confounding Variable: "A variable which is not a factor being considered in an observational study or experiment, but which may be at least partially responsible for the observed outcomes. Experimental design methods use randomization to minimize the effect of confounding variables, but that is not possible in observational studies. The possibility of one or more confounding variables is one of the biggest problems in trying to makes inferences based on observational studies."


    According to this wiki article (https://en.wikipedia.org/wiki/Confounding), one difference between the two is that a confounding relationship assumes that there is a particular relationship between the variables (i.e. that the confound variable causes the dependent and independent variables, which have direct casual relationship) .
    In contrast, an extraneous variable could maybe also be a mediating variable (. I'm not really too sure about this though, just a thought i had after seeing that article. I guess when people use these terms they may not be thinking of a really specific definition in mind anyway.
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    (Original post by iammichealjackson)
    Hmm, i thought they were different but looked up the definitions in the Oxford Psychology Dictionary and they seem to be the same.

    I mostly read "extraneous variables" in the context of observational studies where one is examining factors that potentially influence correlations between variables. In contrast, confounding variable seems to be used much more often in relation to experimental designs, and refers to a factor that differs between the control and experimental group, because the researchers failed to account for it.

    Extraneous Variable: "In statistics and research design, a variable that is of no immediate interest to a researcher but is capable of influencing variables that are of interest. In experimental design, such an extraneous variable is capable of influencing the dependent variable, and it is normally controlled by randomization; when it cannot be controlled, efforts are often made to measure and allow for it. Also called a nuisance variable."

    Confounding Variable: "A variable which is not a factor being considered in an observational study or experiment, but which may be at least partially responsible for the observed outcomes. Experimental design methods use randomization to minimize the effect of confounding variables, but that is not possible in observational studies. The possibility of one or more confounding variables is one of the biggest problems in trying to makes inferences based on observational studies."


    According to this wiki article (https://en.wikipedia.org/wiki/Confounding), one difference between the two is that a confounding relationship assumes that there is a particular relationship between the variables (i.e. that the confound variable causes the dependent and independent variables, which have direct casual relationship) .
    In contrast, an extraneous variable could maybe also be a mediating variable (. I'm not really too sure about this though, just a thought i had after seeing that article. I guess when people use these terms they may not be thinking of a really specific definition in mind anyway.
    Thank you for providing detailed explanations. I didn't know that it depended on the type of study.

    I think the terms are used interchangeably.

    Apparently, one is more serious than the other if it affects your research but I don't remember which one.

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    Well a confounding variable is definitely a big problem, in any type of study as they increase the risk of a type 1 or 2 error and if not accounted for, makies it very hard to say how valid your study or results are.

    The two sound like they are the same thing to me, or so close as not to make any real difference. But I would say that a confound is the most serious as that's the one I remember learning about in stats specifically.
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    An extraneous variable (e.g, mood or weather) is something with the potential to, but has not yet, screwed up your results in someway.

    An extraneous variable only becomes a confounding variable when it actually affects the results of the experiment, because the extraneous variable is actually physically 'confounding' results.
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    (Original post by _Sinnie_)
    Well a confounding variable is definitely a big problem, in any type of study as they increase the risk of a type 1 or 2 error and if not accounted for, makies it very hard to say how valid your study or results are.

    The two sound like they are the same thing to me, or so close as not to make any real difference. But I would say that a confound is the most serious as that's the one I remember learning about in stats specifically.
    (Original post by bamboolie)
    An extraneous variable (e.g, mood or weather) is something with the potential to, but has not yet, screwed up your results in someway.

    An extraneous variable only becomes a confounding variable when it actually affects the results of the experiment, because the extraneous variable is actually physically 'confounding' results.
    Thank you both very much!

    This explains the distinction between the two clearly.

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