Types of bias

Question 1

tendency of subjects to change behavior due to their awareness of being studied

Answer 1

Hawthorne effect aka Observer effect

Question 2

selection bias created from, for example, choosing to use hospital pts as control group

Answer 2

Berkson’s bias

Question 3

apparent prolongation of survival from early detection of disease from screening; however, actual prognosis is not changed.

Answer 3

Lead time bias

Question 4

researchers belief in the efficacy of a treatment affects the outcome.

Answer 4

Pymgalion effect

Question 5

inaccurate recall by pts when filling out questionnaires

Answer 5

recall bias