Teaching Activities Ethics and randomization Randomization is used in clinical trials and is necessary to appropriately evaluate a new treatment’s efficacy. Ask your students to consider this scenario: A close family member has been diagnosed with a serious, life-threatening disease. A new, experimental treatment is currently being tested and preliminary results show much promise. Your loved one is currently receiving the standard treatment that has questionable effectiveness so far. The question is: do you advise this person to forego the standard treatment and participate in a study in which random assignment is used? If they participate, they could receive a promising new treatment, but there is a chance that your family member would be assigned to a control condition and get a placebo. Random selection and assignment Demonstrate the effectiveness of randomization and the differences between random selection and random assignment by using your class as a population. Number the students in class from 1 to N. Use a random number table to randomly select a sample. Discuss how the results of your experiment can be generalized to the class as a whole. Randomly assign students from your sample to one or two experimental groups. Point out to students how various subject characteristics (e.g., gender, age, height, eye color, marital status) are spread across both groups and therefore are not confounding. In other words, the groups are approximately equal with respect to many variables. You can augment this activity by varying size of the sample randomly selected. Remind the students that small sample sizes pose problems. Counterbalancing Provide several experimental scenarios that did not use counterbalancing. What are the possible reasons for the obtained results? Point out how confounding variable could have affected the results possibly leading to a Type I or Type II error. Wadsworth’s Research Methods Workshop http://www.wadsworth.com/psychology_d/templates/student_resources/workshops/resch _wrk.html The Wadsworth’s Research Methods Workshop web site includes a workshop entitled Controls that contains information on how to eliminate factors that jeopardize the validity of research conclusions. The workshop begins by reviewing general strategies to achieve control, such as preparation of the research setting and random assignment of participants to experimental groups. Students are given practice in recognizing factors that introduce bias into a study. Counterbalancing techniques and use of replication as a control are also discussed.
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