Question

In randomized controlled trials, people are randomly assigned to each category to offset any potential _____.

Answer 1

In randomized controlled trials, people are randomly assigned to each category to offset any potential bias.

Selection bias is the phenomenon where the selection of people or groups is not adequately randomized to offset potential bias in research studies. This in turn does not ensure that the study samples included in research are representative of the population needed to be tested on.

Answer 2

"Selection bias."
   Researchers must control for biases that they (the researchers) or participants may have while formulating groups. It allows for people to be sorted into test groups with lessened possibility of being picked based on a pre-existing characteristic.