Measures the general belief about whether reinforcements (rewards and punishments) are controlled by one's own behaviour (internal locus of control) or by outside forces such as luck, fate, or powerful others (external locus of control). One of the most influential personality constructs in psychology, predicting health behaviour, academic achievement, political participation, consumer decision-making, and occupational outcomes. Internals take more preventive health action, engage in more information search before purchase decisions, show higher financial planning behaviour, and are more resistant to persuasion attempts that rely on authority or social proof. The IE Scale is the foundational measure of this construct with over 50 years of validation.
Forced-choice pairs (A vs B; 6 filler items, 23 scored items)
Scored as number of External responses (0–23); higher = more external. The IE Scale is in the public domain. Internals engage in more pre-purchase information search, are more resistant to high-pressure sales, and show better health behaviour compliance. Widely used as a moderator variable in health communication, financial literacy, and consumer behaviour research. Domain-specific LOC scales (health, academic, financial) have higher predictive validity for specific behaviours.
Rotter, J.B. (1966). Generalized expectancies for internal versus external control of reinforcement. Psychological Monographs: General and Applied, 80(1), 1–28.
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