What is selection bias, why is it important and how can you avoid it?

What is selection bias, why is it important and how can you avoid it?



Answer: Selection bias is the term used to describe the situation where an analysis has been conducted among a subset of the data (a sample) with the goal of drawing conclusions about the population, but the resulting conclusions will likely be wrong (biased), because the subgroup differs from the population in some important way. Selection bias is usually introduced as an error with the sampling and having a selection for analysis that is not properly randomized.


It can be avoided by taking a random sampling of the population and testing to make sure that the subgroup looks like the population along many measures (age, gender, education).

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