Sociology 3306A/B Chapter Notes - Chapter 6: Design Of Experiments, Measuring Instrument, Treatment And Control Groups

• School: Western University
• Department: Sociology
• Course: Sociology 3306A/B
• Professor: Jeremy Kerr

Document Summary

Uncontrolled extraneous variables that pose explanations of study results that rival the hypothesized effect of the independent variable. Events in the subjects environment, other than the intended experimental manipulation, that occur during the course of an experiment that may affect the outcome. Unwanted changes in the characteristics of the measuring instrument or measurement procedure. Tendency for extreme scorers on one measurement to move (regress) closer to the mean score on a later measurement. Systematic differences in the composition of control and experimental groups. Loss of subjects during course of a study (aka mortality) Existence of varying dropout rates among conditions of an experiment which tends to make the conditions nonequivalent in composition. Any psychological or physiological changes taking place within subjects that occur over time, regardless of experimental regulations. Changes in what is being measured that are brought about by reactions to the process of measurement; effects of being measured once on being measured a second time.