Question

What are the three steps in assessing whether bias exists in a study? Explain each of them

Answer 1

Several aspects of the study design, conduct, and analysis should be assessed by the critical reader regarding the three main types of bias:

(1) selection bias: are the study subjects corresponding to the target population, and are the subjects in the study arms comparable;

(2) classification bias: how was the information regarding exposure and disease collected, and was the information collected in a comparable manner;

and (3) confounding bias: has there been a systematic effort to identify and measure potential confounders, and is there information regarding how the potential confounders are distributed between the comparison groups?