# Freshman Statistics Seminar

** Week 13: Hazard Ratios**

**Marta Shore**

**Objective:**

- understand hazard ratios
- interpret hazard ratios

**Suggested Lesson Structure:**

Have the class read the handout from Medpage today entitled “Lifestyle Changes Effective in Preventing Type 2 Diabetes” before they come to class. They don’t have to understand everything, just get a sense of how common relative risk and hazard ratios are.

There’s a handout on hazard ratios that references the paper by SL Spruance, JE Reid, M Grace, and M Samore called “Hazard Ratio in Clinical Trials” (Antimicrob.Agents Chemother. 48(8) 2787-2792). The handout explains the basic ideas of hazard ratios without all the technicalities of the original paper. It is recommended that the students read the handout during the first 15-20 minutes of class. These concepts aren’t easy, so make sure there’s no confusion before going on. Then the active learning module should be done.

**Active Learning Modules:**

Each student should work through the sheet. The data is designed so that both the treatment and control groups have expoential survival rates. The goal is to simply find the values at each day, and then graph the two curves on the same graph. The graph should be in the stepwise form shown in the Spruance paper.

The class should discuss the discussion questions. Finally, at the end of class, it is a good idea to point out that this is simulated data. In real life, hazard ratios are often not this constant, and complicated statistical methods are used to figure out the hazard ratio.

**Download Exercise:**

Week 13 Exercise (week13exercise.xls)

**Additional Links:**