Self-efficacy is the major concept of Bandura's social cognitive theory. Self-efficacy is influenced by four important sources of information: performance accomplishments, vicarious experience, verbal persuasion, and physiological information. Other determinants of self-efficacy are internal personal factors and external environmental factors. The degree of change in self-efficacy is partly a function of the variability and the controllability of its determinants. Level of self-efficacy predicts how people are functioning in terms of choice of behavior, effort expenditure and persistence, thought patterns and emotional reactions. Measurement of self-efficacy is related to three dimensions: magnitude, strength and generality. Self-efficacy should be measured in terms of particularized judgments of capability that may vary across realms of activity, different levels of task demands within a given activity domain, and different situational circumstances.