PSYCH 2300 Chapter Notes - Chapter 11: Spontaneous Remission, Internal Validity, Confounding
1 Apr 2018
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Ch 11: more on experiments: confounding and obscuring variables. 3 most common threats = design confounds, selection effects, and order effects. One-group, pretest/posttest design - you only measure 1 group on a pretest and posttest measuring the same thing. This design is too problematic to use. 6 potential internal validity threats in one-group, pretest/posttest designs. Maturation threats, history threats, regression threats, attrition threats, testing threats, and instrumentation threats. Maturation threat - a change in behavior that emerges more or less spontaneously over time. A regression threat refers to a statistical concept called regression to the mean: when a performance is extreme at time 1, the next time that performance is measured at time. 2, it is likely to be less extreme -- that is, closer to a typical or average performance. The mean is the average of all the performances.
