# Learning Objectives

A. Learn to apply the main features of a cohort study

- Formulate a research hypothesis
- Define the 'at risk' population
- Define eligibility criteria for study participants
- Define exposure and outcome
- Understand cohort studies based on the timing of events

B. Conduct data analyses consistent with a cohort design

- Calculate and interpret the risk ratio using frequencies
- Calculate and interpret the rate ratio using person-time information
- Calculate and interpret the standardized incidence ratio (SIR)

C. Interpret your findings

- Understand the differences between a risk ratio and a rate ratio
- Discuss how subgroup analyses influence our certainty about study results
- Discuss the value of age standardization