Review Questions for Chapter 12

§12.1 Introduction

  1. Name the two major types of errors in epidemiologic research.
  2. How do parameters differ from estimates?
  3. Describe the notational convention used to distinguish parameters from estimators.
  4. Provide a synonym for systematic error.
  5. Provide a synonym for random error.
  6. Provide an antonym for biased.
  7. Provide an antonym for precise.
  8. List ways in which random error differs from systematic error.

§12.2 Random Error 

  1. [True or false?] Probability models are used to quantify and adjust for bias in epidemiologic research.
  2. [T/F] Objective and subjective views of probability are not compatible with each other. 
  3. What two statistical procedures are used to addressing random error in epidemiologic data?
  4. *NEW* Suppose the sample size an observation study could be expanded to be infinitely large. What sources of error would be eliminated, and which sources of error would not?

§12.3 Systematic Error

  1. Name three categories of bias in epi studies.
  2. [True or false?] Nondifferential misclassification bias measures of effect away from the null.
  3. [True or false?] A bias away from null tends to underestimate risks. 
  4. Define confounding.
  5. List the properties of a confounder.
  6. What does the Latin word confundere mean?
  7. Use of hospitalized controls in case-control studies could result in this type of bias.
  8. *NEW* Will a large study have less bias than a small study?
  9. *NEW* Subjects who experience an adverse outcome (cases) tend to give responses about potential causes of the adverse outcome that differ from those given by those that did not experience the outcome (non-cases). What type of bias can this cause?
  10. *NEW* What type of bias would occur if the code book for the data from an epidemiologic study was mixed up so that all exposed individuals were mistakenly identified as non-exposed, and vice-versa? 
  11. *NEW* In what situations will an extraneous risk factor not confound the association between an exposure and disease?
  12. *NEW* This question is from Rothman (2002, p. 112). Those who favor representative studies claim that one cannot generalize a study to a population whose characteristics differ from those in the study population. Thus, a study of smoking and lung cancer in men would tell nothing about the relation between smoking and lung cancer in women. Give the counterarguments. (HInt: IF the study were conducted in London, would the results apply to those who lived in Paris?)
  13. In pharmacoepidemiologic studies, "confounding by indication" occurs when those who are given a certain drug have a different medical condition or severity of medical condition from those who did not take the drug. Is this truly a problem related to confounding, or is it better to classify this as a type of selection bias?

Last update: 04/25/2009

Key