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Say we need to survey a shopping mall but havent created a survey questionnaire in advance. The guy who is going to conduct the survey will ask questions based on live response from the people at the mall. So in this way there the survey can be considered online (plan as you go).

Question: Is the next question based on the response of the initial question considered confounding factor or the initial question is considered confounding factor to the next question being asked?

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Is the next question based on the response of the initial question considered confounding factor or the initial question is considered confounding factor to the next question being asked?

It only makes sense to talk of confounding when there are at least 3 variables being considered.

It might be helpful to draw a DAG but the situation seems fairly simple. Let's think about 3 questions and assume no other variables are involved.

If the first question has a causal effect on the 2nd question and the 3rd question then the first question is a confounder. The 2nd question cannot be a confounder because it cannot cause the first question. The 2nd question is a mediator

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  • $\begingroup$ I see it makes some sense now. So what if the first question leads to chain of questions, DAG being a chain 1st and 2nd question has a causal effect on 3rd, while 1st, 2nd and 3rd has a causal effect on 4th and so on. The we still say first question is a confounder? So it not really a markov chain but a bayes chain. $\endgroup$
    – user0193
    Sep 29, 2020 at 12:58
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    $\begingroup$ Whenever we think about confounding it has to be in relation to a particular causal path. So, with a chain of 4, Let's call them A, B, C and D, A would be a confounder of the B-> C path and the B -> D path. For the C -> D path, both A and B would be confounders. Once you have 4 or more variables it really makes things easier to draw a DAG :) $\endgroup$ Sep 29, 2020 at 13:13
  • $\begingroup$ Perfect! This makes so much sense indeed! $\endgroup$
    – user0193
    Sep 29, 2020 at 14:27

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