KEY Review Questions for Chapter 9 

1. (1) The population to which the effect applies (2) The exposure ("independent variable") (3) the health outcome or disease being studied ("dependent variable") (4) the expected dose-response (5) the expected time-response and (6) extraneous factors that could confound results or modify the effect of the exposure
2. This is the description of how the exposure dose influences the risk of the outcome.
3. This is a description of the temporal relationship between the exposure and the occurrence of the outcome. 
4. False. For an excellent commentary,  see Maclure, M. (1991). Taxonomic axes of epidemiologic study designs: a refutationist perspective. Journal of Clinical Epidemiology, 44(10), 1045-1053  [Link to abstract].
5. In experimental studies, the exposure is assigned according by  mechanisms built into the study protocol. In non-experimental studies, the exposure is studied without interference.  
6. Randomization balances groups with respect to measured and unmeasured extraneous factors that could otherwise confound results.
7. This means that you should design the study to try to isoloate the effects of the exposure. 
8. This is an aggregate-level measurement
9. This is a cross-sectional  measurement 
10. True  
11. Cohort studies evaluate the experience of all people in a source population. Case-control studies evaluate the experience of all cases and a subset of non-cases. 
12. Ecological studies use aggregate-level data.  
13. Longitudinal measurements require follow up of individuals over time. Cross-sectional measurements related to a single cross-section in time. 
14. (1) = Ecological (2) = Cross-sectional study (3) = Case-control (4) = Cohort (5) = Trial

Last update: 11/23/2008