2.6 Optional: Understanding studies
(Answers are available in Sect. A.2)
Answer these questions:
Identify the variables involved.
Explain whether the study is observational or experimental.
If the study is experimental, determine if the principles of randomization, control, blinding and double-blinding, and blocking have been used. Also determine if it is a true experiment or a quasi-experiment.
If the study is observational, determine if the study is retrospective, prospective or cross sectional.
Which one of the following, if any, would be a potential lurking variable? Explain.
- The general health of the subject.
- The average amount of water consumed each day by the subjects.
Is a cause-and-effect relationship reasonable? Explain.
What are the limitations of the study?
Identify the units of observation, and the units of analysis.
What did you learn from this report?
GISSI-Prevenzione Investigators. 1999. “Dietary Supplementation with N-3 Polyunsaturated Fatty Acids and Vitamin E After Myocardial Infarction: Results of the GISSI-Prevenzione Trial.” The Lancet 354: 447–55.