Question

PLease answer the following about bias in cohort studies.

1.Prospective Cohort

     a…What is a bias that this study design avoids?   

     b…What is a bias that this study design is less likely to have?         

     c…What kind of bias this study design mostprone to?         

     d…What kind of bias this study design prone to?      

2.Retrospective Cohort

     a…What is a bias that this study design avoids?       

     b…What is a bias that this study design is less likely to have?         

     c…What kind of bias this study design mostprone to?         

            d…What kind of bias this study design prone to?

Answer 1

1 Prospective Cohort Study

a) i)Selection Bias : selection criteria is to be crlearly defined ,ii) information bias : wrongly recorder information to be avoided .. iii)Confounding Bias : Mixing of effects when a confounder associated with the exposure .

b) measurment bias is less likely to have occure in prospective cohort . because the exposed group is continuously monitered by the investigator

C) Selection bias is most prone to happen in cohort studies

2 . Retrospective Cohort Study

a) i)Selection Bias : selection criteria is to be crlearly defined ,ii) information bias : wrongly recorder information to be avoided .. iii)Confounding Bias : Mixing of effects when a confounder associated with the exposure .

b) follow up bias .( Previously collected data to be used in retrospective hence follow up measurment is not required .

c ) information Bias : Recorded /published data error of exposed group is a major concern in retrospective study