All::Clinical Science::Study Design::Bias
Intro
What is meant by bias in study design?
A situation in a trial where one outcome is systematically favoured
What is Selection bias?
Error in assigning individuals to groups leading to differences which may influence the outcome
What is Recall bias?
Difference in the accuracy of the recollections retrieved by study participants, possibly due to whether they have disorder or not
What is Publication bias?
Failure to publish results from valid studies, often as they showed a negative or uninteresting result.
What is Work-up bias/verification bias?
clinicians may be reluctant to order the gold standard test unless the new test is positive, as the gold standard test may be invasive
What is Expectation bias?
Observers may subconsciously measure or report data in a way that favours the expected study outcome
What is the Hawthorne effect?
Describes a group changing it's behaviour due to the knowledge that it is being studied
What is Late-look bias?
Gathering information at an inappropriate time
What is Procedure bias?
Occurs when subjects in different groups receive different treatment
What is Lead-time bias?
where early diagnosis of a disease falsely makes it look like people are surviving longer