Internal Control Index

The Internal Control Index is a measure of internal external locus of control developed by Duttweiler (1984).

Psychometric properties
It has reasonably good psychometric properties and in her paper on this scale, Duttweiler notes many problems with Rotter's I-E Scale, including problems with its forced choice format, its susceptibility to social desirability and her observation that studies which have subject the scale to factor analysis suggest it is not assessing an entirely homogeneous concept. She also notes that, while other scales existed in 1984 to measure locus of control, "they appear to be subject to many of the same problems" (Duttweiler, 1984, p211). She developed the ICI to assess several variables especially pertinent to internal locus - cognitive processing, autonomy, resistance to social influence, self-confidence and delay of gratification. After administration of this scale to 133 students at Gainesville Junior College in Georgia, United States, she found the scale to have good internal reliability, with a Cronbach's alpha of .85. Unlike the forced-choice format used on Rotter's scale, Duttweiler's 28-item ICI uses a Likert-type scale, in which people have to state whether they would rarely, occasionally, sometimes, frequently or usually behave as specified by each of 28 statements.