Abstract
The Internal Control Index (ICI), developed by Patricia C. Duttweiler in 1984, is a 28-item psychometric instrument designed to measure internal locus of control. Constructed to overcome the methodological and psychometric vulnerabilities of earlier instruments—most notably the forced-choice format, susceptibility to social desirability bias, multidimensional confounding, and low internal consistency found in Julian B. Rotter’s Internal-External (I-E) Scale—the ICI focuses exclusively on the cognitive and behavioral variables characteristic of internal locus of control orientation. The scale assesses five theoretical dimensions related to internality: autonomy, cognitive processing, delay of gratification, resistance to influence attempts, and self-confidence. Psychometric evaluations across multiple developmental phases (including a tryout sample of N = 548, a field test sample of N = 684, and a cross-validation sample of N = 133) revealed a stable two-factor structure: Factor 1, designated as Confidence in One’s Own Ability, and Factor 2, designated as Autonomous Behavior. The instrument demonstrates strong internal consistency, yielding Cronbach’s alpha coefficients of .84 in the field test and .85 in the replication study. Convergent validity is evidenced by significant correlations with Herbert L. Mirels’ Factor I (Personal Control) of the Rotter I-E Scale (p < .001). Administered via a 5-point Likert-type response scale ranging from Rarely to Usually, the ICI provides researchers and clinicians with a reliable, unidimensional-to-bidimensional index of an individual’s generalized expectancy that outcomes are contingent on their own efforts, skills, and autonomous decisions rather than external forces such as fate, chance, or powerful others.
Keywords
Internal Control Index, Locus of Control, Psychometrics, Patricia C. Duttweiler, Autonomous Behavior, Self-Confidence, Rotter I-E Scale, Social Learning Theory, Expectancy Theory, Instrument Validation
Authors
The Internal Control Index was conceived, developed, and empirically validated by Dr. Patricia C. Duttweiler. At the time of the instrument’s initial development and psychometric publication (1984), Dr. Duttweiler conducted her research within the context of adult and higher education measurement, later serving in prominent research and leadership roles, including affiliations with the National Dropout Prevention Center at Clemson University and the Southwest Educational Development Laboratory (SEDL) in Austin, Texas. Her academic scholarship has focused extensively on educational psychology, dropout prevention, at-risk student intervention strategies, and the cognitive-motivational factors that facilitate academic and vocational persistence.
Purpose
The primary purpose of the Internal Control Index is to provide an internally consistent, methodologically robust, and psychometrically sound assessment of internal locus of control. During the late 1960s and 1970s, the assessment of locus of control was dominated by Julian Rotter‘s 29-item Internal-External (I-E) Scale (1966). Despite its historical prominence, researchers identified several recurring empirical flaws in Rotter’s measure:
- Forced-Choice Artifacts: The forced-choice ipsative design forced respondents to choose between an internal statement and an external statement, which generated artificial response friction, confounded statistical analysis, and compromised participant engagement.
- Vulnerability to Social Desirability: Many internal items were perceived as socially desirable, skewing distributions and generating response sets.
- Confounding External Subdimensions: Rotter’s scale collapsed diverse external orientations—such as belief in luck, fate, chance, unjust systems, and powerful others—into a single composite score, often blurring the exact psychological meaning of the resulting score.
- Suboptimal Reliability: Published internal consistency estimates for Rotter’s I-E Scale frequently hovered between .65 and .79, reflecting psychometric heterogeneity that restricted its utility in individual diagnostic assessment.
Recognizing that externality comprises multidimensional variables that may not simply be the mirror opposite of internality, Duttweiler chose to measure internality directly. The ICI assesses the degree to which an individual perceives themselves as the primary agent of their personal outcomes across educational, occupational, and interpersonal domains. The instrument is widely utilized in clinical, educational, and organizational research to examine the relationship between internal agency and academic performance, vocational achievement, leadership emergence, stress resilience, treatment adherence, and psychological wellbeing.
Psychological Construct
Locus of control represents an individual’s generalized expectancy regarding the causal relationship between their personal behavior and subsequent reinforcements. Duttweiler conceptualized internality not merely as the absence of external attribution, but as an active, integrated constellation of behavioral inclinations, cognitive processing patterns, and affective self-perceptions.
Theoretical Domains of Internality
During the exploratory construction phase, Duttweiler delineated five key domains associated with internal locus of control:
- Autonomy: The disposition to act independently of excessive social influence, peer pressure, or institutional conformity. Autonomous individuals select goals based on intrinsic value systems rather than external directives.
- Cognitive Information Processing: A proactive cognitive style characterized by information seeking, problem-solving, and analyzing environmental cues prior to decision-making. Internals actively gather data to master their environments.
- Delay of Gratification: The self-regulatory capacity to postpone immediate rewards in pursuit of long-term objectives, resting on the belief that sustained effort will yield contingent future outcomes.
- Resistance to Social Influence: Psychological assertiveness and self-direction when confronted with persuasive appeals, peer coercion, or conflicting authority, allowing individuals to uphold their own judgment.
- Self-Confidence: Belief in one’s personal competence, intellectual capabilities, and executive functioning to navigate complex life situations and assume leadership roles.
Empirical Factor Dimensions
Factor analyses conducted by Duttweiler revealed that these five theoretical domains distill into two robust, correlated latent dimensions:
- Factor 1: Confidence in One’s Own Ability: Reflects personal agency, decisiveness, perceived competence, intellectual curiosity, willingness to take calculated risks, and an active orientation toward problem-solving (e.g., “I like jobs where I can make decisions and be responsible for my own work”).
- Factor 2: Autonomous Behavior: Reflects independence from external praise, resistance to conformity, rejection of peer pressure, and self-reliance during ambiguous or demanding tasks (e.g., “I need frequent encouragement from others to keep me working at a difficult task” [reverse-scored]).
Theoretical Framework
The theoretical architecture of the Internal Control Index is rooted in Social Learning Theory, pioneered by Julian B. Rotter (1954, 1966). Within this framework, the potential for a given behavior to occur in a specific psychological situation ($BP$) is a function of the expectancy ($E$) that the behavior will lead to a particular reinforcement ($RA$) and the psychological value of that reinforcement ($RV$), formulated mathematically as:
BPs,r,v = f(Es,r,v & RVr,v)
Rotter posited that when individuals encounter novel or ambiguous situations, they rely on generalized expectancies derived from cumulative past learning histories. Those who develop an internal locus of control believe that outcomes are contingent upon their own behavior, ability, or effort. Conversely, those with an external locus of control perceive reinforcements as determined by luck, chance, fate, or powerful external figures.
Duttweiler extended Rotter’s framework by integrating insights from Albert Bandura‘s (1977) Self-Efficacy Theory and early foundations of Self-Determination Theory (Deci & Ryan, 1985). While locus of control traditionally describes outcome contingencies (“Does my action produce the outcome?”), Bandura emphasized efficacy expectations (“Can I execute the required behavior?”). Duttweiler recognized that authentic internal behavior requires both an expectancy of outcome contingency and the self-confidence necessary to execute autonomous actions. By filtering out confounding dimensions of external fatalism, the ICI operates as a targeted measurement of internal agency and personal self-determination.
Validity
The Internal Control Index underwent rigorous empirical validation across diverse higher education and adult populations, demonstrating strong construct, convergent, and content validity.
Construct and Content Validation
The scale was developed across four progressive stages. The initial item pool was generated from a comprehensive review of literature examining characteristics separating internals from externals. Items judged ambiguous, overly context-specific, or susceptible to obvious social desirability biases were eliminated. The instrument was pretested and refined across exploratory cohorts (N = 548) comprising junior college, continuing education, and university students before administration to the primary field test sample (N = 684).
Convergent Validity
Convergent validity was established by comparing the ICI with Mirels’ Factor I of the Rotter I-E Scale. Herbert L. Mirels (1970) demonstrated that Rotter’s scale comprises at least two distinct subscales: Factor I (Personal Control, measuring an individual’s belief in their ability to govern their own life) and Factor II (System Control, measuring beliefs regarding sociopolitical events). Duttweiler correlated scores on the ICI with Mirels’ Factor I, obtaining a statistically significant correlation (p < .001). This confirmed that the ICI captures personal agency while removing systemic and political attributions that previously attenuated Rotter’s scale.
Criterion and Applied Validity
Subsequent investigations have substantiated the predictive and criterion validity of the ICI across multiple settings:
- Academic Performance: Smith (2003) confirmed significant positive associations between higher ICI scores and educational attainment, academic self-regulation, and persistence in college cohorts.
- Occupational Leadership and Satisfaction: Stachowiak (2010) examined the ICI within organizational and academic environments, discovering that professionals with higher internal control scores exhibited significantly higher job satisfaction, enhanced intrinsic motivation, and lower burnout.
Reliability
The psychometric evaluation of the Internal Control Index demonstrates high internal consistency across diverse adult and postsecondary samples.
- Field Test Sample (N = 684): The initial field administration yielded a Cronbach’s alpha coefficient of .84, reflecting strong internal consistency and item homogeneity across demographic categories.
- Cross-Validation Sample (N = 133): In an independent replication sample composed of students from Gainesville Junior College, the instrument produced a Cronbach’s alpha coefficient of .85.
- Item-Total Correlations: Corrected item-total score correlations across both validation cohorts confirmed that each of the 28 items contributed meaningfully to the total score, with corrected correlations generally ranging from .25 to .55.
- Subsequent Literature: Subsequent academic studies utilizing the ICI across health, vocational, and educational domains have consistently reported Cronbach’s alpha values between .80 and .87, confirming the stability of the index over time and across diverse sample demographics.
Factor Analysis
Duttweiler conducted principal axis factor analyses followed by Varimax orthogonal rotation on both the primary field test sample (N = 684) and the Gainesville Junior College replication sample (N = 133). In both analyses, scree plots and eigenvalue criteria converged on a clear, stable two-factor solution.
Factor 1: Confidence in One’s Own Ability
This factor captures personal efficacy, willingness to assume leadership, proactive problem resolution, and intrinsic task engagement. In the field test sample, 14 items loaded predominantly on this factor:
- Field Test Items: 3, 4, 5, 7, 9, 10, 13, 15, 16, 18, 20, 21, 25, and 28.
- Replication Sample Items: 13 items loaded onto this factor in the Gainesville sample (Items 1, 3, 7, 9, 10, 12, 13, 15, 16, 19, 20, 23, and 28).
Factor 2: Autonomous Behavior
This factor reflects psychological independence, resistance to peer and authority pressures, self-reliance, and detachment from external praise. In the field test sample, 13 items loaded predominantly on this factor:
- Field Test Items: 2, 6, 8, 11, 12, 14, 17, 19, 22, 23, 24, 26, and 27.
- Replication Sample Items: 14 items loaded onto this factor in the Gainesville sample (Items 1, 2, 6, 8, 11, 14, 16, 18, 20, 21, 22, 24, 26, and 27).
Minor cross-loading variations between the field test and replication cohorts (e.g., items 1, 12, 18, and 20) reflect sample-specific variances between large heterogeneous adult populations and smaller regional collegiate groups. Nevertheless, the overarching distinction between cognitive-perceived competence (Factor 1) and behavioral self-reliance (Factor 2) remained robust across exploratory and confirmatory replications.
Instrument / Measurement Tool
The Internal Control Index is structured as follows:
- Construct: Internal Locus of Control.
- Respondent Age Range: Adolescents, college students, and adults (ages 16+).
- Administration Format: Self-report paper-and-pencil or computer-administered questionnaire.
- Number of Items: 28 declarative statements.
- Estimated Completion Time: 8 to 12 minutes.
- Response Format: 5-point Likert-type scale:
- Rarely = 5
- Occasionally = 4
- Sometimes = 3
- Frequently = 2
- Usually = 1
- Reversed Scoring Protocol: Scoring is reversed for 14 items: 3, 5, 7, 9, 10, 12, 13, 15, 16, 18, 20, 21, 25, and 28. For these items, values are inverted (Rarely = 1, Occasionally = 2, Sometimes = 3, Frequently = 4, Usually = 5) so that higher points consistently reflect higher internal locus of control.
- Total Score Range: 28 to 140 points. Higher composite scores represent a stronger internal locus of control orientation.
Permissions & Fee and Test Year
The Internal Control Index was officially published in 1984 in the journal Educational and Psychological Measurement (Sage Publications). As an academic psychometric instrument published in the public scholarly literature, the ICI is generally accessible for non-commercial educational, clinical, and academic research purposes without licensing fees, provided proper citation is given to Dr. Patricia C. Duttweiler and the publishing journal. Researchers intending to incorporate the scale into commercial assessment platforms, published diagnostic batteries, or funded organizational evaluations should contact the copyright holders or Sage Publications to ensure licensing compliance.
References
- Bandura, A. (1977). Self-efficacy: Toward a unifying theory of behavioral change. Psychological Review, 84(2), 191–215. https://doi.org/10.1037/0033-295X.84.2.191
- Deci, E. L., & Ryan, R. M. (1985). Intrinsic motivation and self-determination in human behavior. Plenum Press. https://doi.org/10.1007/978-1-4899-2271-7
- Duttweiler, P. C. (1984). The Internal Control Scale: A newly developed measure of locus of control. Educational and Psychological Measurement, 44(2), 209–221. https://doi.org/10.1177/0013164484442004
- Levenson, H. (1974). Activism and powerful others: Distinctions within the concept of internal-external control. Journal of Personality Assessment, 38(4), 377–383. https://doi.org/10.1080/00223891.1974.10119988
- MacDonald, A. P., Jr. (1973). Measures of internal-external control. In J. P. Robinson & P. R. Shaver (Eds.), Measures of social psychological attitudes (pp. 169–243). Survey Research Center, Institute for Social Research, University of Michigan.
- Mirels, H. L. (1970). Dimensions of internal versus external control. Journal of Consulting and Clinical Psychology, 34(2), 226–228. https://doi.org/10.1037/h0029005
- Rotter, J. B. (1954). Social learning and clinical psychology. Prentice-Hall. https://doi.org/10.1037/10788-000
- Rotter, J. B. (1966). Generalized expectancies for internal versus external control of reinforcement. Psychological Monographs: General and Applied, 80(1), 1–28. https://doi.org/10.1037/h0092976
- Smith, V. L. (2003). Analysis of locus of control and educational level utilizing the Internal Control Index (Master’s thesis, Marshall University). Marshall Digital Scholar.
- Stachowiak, B. J. (2010). Job satisfaction and locus of control in an academic setting (Doctoral dissertation, Pepperdine University). ProQuest Dissertations and Theses Global.