effect coding

in regression analysis, a procedure in which values of 1 or −1 are assigned to represent the categories of a dichotomous variable (or 1, 0, and −1 for a trichotomous variable). The results obtained for the group indicated by values of 1 are then interpreted relative to the larger group comprising all participants. For example, a researcher could assign values of 1 to individuals in an experimental group and values of −1 to those in a control group. He or she could conclude that there is a treatment effect if the experimental group has a mean different from the grand mean across all of the individuals. Compare contrast coding; dummy variable coding.

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Psychology term of the day

December 26th 2024

mental disorder

any condition characterized by cognitive and emotional disturbances, abnormal behaviors, impaired functioning, or any combination of these. Such disorders cannot be accounted for solely by environmental circumstances and may involve physiological, genetic, chemical, social, and other factors. Specific classifications of mental disorders are elaborated in the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (see DSM–IV–TR; DSM–5) and the World Health Organization’s International Classification of Diseases. Also called mental illness; psychiatric disorder; psychiatric illness; psychological disorder. See also psychopathology.