Clinical Epi. Bias-Chance-Confounding

Question 1

describe interviewer bias and recall bias

Answer 1

• interviewer bias: an interviewer’s knowledge may influence the structure of questions and the manner of presentation, which may influence responses
• recall bias: those with a particular outcome or exposure may remember events more clearly or amplify their recollections

Question 2

describe steretyping, halo effect and non-verbal bias

Answer 2

• stereotype: forming an opinion about a candidate on the basis of gender, race, religion, etc.
• halo effect: allowing a positive or negative trait to overshadow all other information provided by the candidate
  
  • if someone is good at one dimension, he/she is perceived to be good at other dimensions as well
• non-verbal bias: placing undue emphasis on a non-verbal characteristic that the candidate possessses

Question 3

describe the healthy worker effect

Answer 3

• found in work-fource studies
  
  • reflects medical screening (military, mining)
• results in better health status initially than general population or certian control population
  
  • reduces risk or delays occurrence of health outcomes of interest

Question 4

describe the Hawthorne effect

Answer 4

• the phenomenon that subject behavior changes by the mere fact that they are being observed

Question 5

describe the Pygmalion effect

Answer 5

Question 6

describe Berkson’s bias

Answer 6

• selection bias that causes hospital cases and controls in a case control study to be systematically different from one another because the combination of exposure to risk and occurrence of disease increases the likelihood of being admitted to the hospital
  
  • This produces a systematically higher exposure rate among hospital patients, so it distorts the odds ratio.

Question 7

describe lead time bias

Answer 7

• screening may lead to earlier diagnosis, which can then seem like a patient is living longer (survival time)