PSY 283 Midterm: Exam 1 Study Guide
18 Feb 2019
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Quasi-experiments: the experimenter makes use of naturally occurring groups. In a quasi-experiment, the experimenter cannot control the independent variable. In a true experiment, researchers would use random assignment . but sometimes that is not possible or ethical. For example, doing a study with alcoholics and non-alcoholics: those are groups that you cannot assign. In a true experiment, you can manipulate the independent variable, but in a quasi-experiment, it is either impossible or unethical to do so, so researchers doing quasi-experiments make use of naturally occurring groups. Natural experiment (quasi-experiment in epidemiology): makes use of naturally occurring circumstances in which subsets of population have different levels of exposure to a supposed causal factor. Ex-post-facto (quasi-experiment): examines whether one or more pre-existing conditions could have possibly caused subsequent differences (dependent variable) in groups of subjects. Useful for when independent variable cannot be manipulated (b/c it would be either impossible or unethical). Cannot determine causality but can strongly suggest it.
