ex post facto design

research that examines past occurrences in order to understand a current state. Although this type of design involves both a dependent variable and an independent variable, the investigator cannot manipulate the latter. For example, a researcher who is interested in determining the effectiveness of a particular television advertisement on consumer behavior may recruit a group of participants who saw the advertisement and a group of participants who did not, yet the researcher has no control over which specific people actually viewed the advertisement. Also called ex post facto study. [from Latin ex post facto, “after the event”]

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Psychology term of the day

July 27th 2024

primary insomnia

in DSM–IV–TR, a sleep disorder characterized by difficulty in initiating or maintaining a restorative sleep to a degree in which the severity and persistence of the sleep disturbance causes clinically significant distress, impairment in a significant area of functioning, or both. The disorder is not caused by a general medical condition or the effects of a substance and is not exclusively an aspect of another sleep disorder or mental disorder. It is termed insomnia disorder in DSM–5. See dyssomnia. Compare primary hypersomnia.