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Select a Professional Development Module:
Key Topics Strategy Scenario Case Study References

Introduction  |  Step 1  |  Step 2  |  Step 3  |  Step 4  |  Step 5  |  Step 6  |  Step 7  |  Step 8  |  Step 9  |  Step 10

Step 10: Maximize the efficiency of your sample.

Given that your primary unit of analysis is the school, you decide that you need as many schools as possible in the intervention and control groups. You decide to randomly assign 20 of the 40 schools in the district with 8th grades to the intervention group and the other 20 to the control group. Then, to maximize efficiency (that is, maintain as high power as possible without adding needlessly to the costs by oversampling the secondary units of analysis), you decide to select 2 teachers per school and 5 students per teacher.