Internal External Locus of Control Scale

The Internal External Locus of Control Scale (I-E Scale) is a researcher-constructed scale published by Julian B. Rotter in 1966. Social Learning Theory provides the theoretical background for which the scale provides a measure of generalized expectancy. The scale relates general expectancy as being either internally or externally controlled. An internally controlled person will perceive his or her destiny as controlled from within, whereas the externally controlled person perceives his or her destiny as controlled by outside forces such as chance, fate, or luck.

Rotter conceived the scale from earlier attempts by Phares and James to create a generalized expectancy scale in which they constructed their scales using the Likert format. Attempting to broaden the test, additional subscales were developed by Rotter for areas including achievement, affection, and general social and political attitudes. What resulted was a 100-item scale containing items comparing an internal belief to an external belief. In order to provide greater control for social desirability, the Likert format was discarded in favor of the forced-choice format. Using item analysis and factor analysis, this test was further reduced to 60 items by Liverant. Item analysis of the 60-item scale resulted in abandoning efforts to measure specific subareas. These items were then excluded. Additional items were also removed if they had a high correlation with the Marlowe-Crowne Social Desirability Scale, had an alternative endorsed more than 85% of the time, had no significant relationship with other items, or had little correlation with one of two criteria. The criteria used to provide [Page 480]validity for the items involved a laboratory task and the coping behavior of tuberculosis patients. This reduced the scale to 23 items, to which six filler items were added for purposes of ambiguity, all in a forced-choice format. Two separate factor analyses determined that one factor accounted for most of the variance.

To score the test, a summation of external choices is made. High scores indicate externality and low scores indicate internality. The distribution of scores tends to be normal, and dividing groups about the median score is commonly used to indicate the split between externals and internals.

The I-E Scale can be used in a variety of situations. Since its conception, the I-E Scale has generated considerable interest and subsequent research. For example, externals have been associated with field dependence and internals with field independence. Interestingly, it has been posited that moderate internal scores should have some relationship to good adjustment. Accordingly, it has been reported that therapeutic outcomes are related to shifts in locus of control; that is, those who improve generally show a shift toward the internal end of the spectrum.