Description

The Interpersonal Check List (ICL-128) is a standardized psychometric instrument developed to assess interpersonal behavior, personality characteristics, and the patterns through which individuals perceive, experience, and interact with other people. Based on Timothy Leary’s Interpersonal Theory of Personality, the questionnaire provides a comprehensive evaluation of interpersonal functioning by examining the attitudes, behavioral tendencies, and emotional responses that shape social relationships across everyday, clinical, educational, and occupational settings.

The theoretical foundation of the ICL-128 proposes that interpersonal behavior can be understood through recurring patterns of dominance, submission, warmth, hostility, cooperation, and independence. These behavioral tendencies influence the quality of interpersonal relationships, communication styles, conflict management, emotional adjustment, and overall psychosocial functioning. By identifying characteristic interpersonal profiles, the questionnaire contributes to a deeper understanding of both adaptive and maladaptive relationship patterns.

The Interpersonal Check List consists of 128 self-report items that evaluate a broad spectrum of interpersonal characteristics, including friendliness, acceptance, cooperation, self-confidence, assertiveness, hostility, aggressiveness, rejection, dependence, submissiveness, emotional responsiveness, and other personality-related interpersonal behaviors. The instrument enables the identification of stable interpersonal styles that may influence relationship quality, occupational functioning, psychological well-being, and therapeutic outcomes.

The ICL-128 is extensively used in clinical psychology, psychiatry, psychotherapy, counseling psychology, personality assessment, organizational psychology, educational psychology, behavioral medicine, and psychological research, where it serves as a valuable instrument for evaluating interpersonal functioning, personality dynamics, and social adjustment.

Data Analysis and Use

Data obtained from the Interpersonal Check List (ICL-128) are analyzed using comprehensive psychometric and statistical procedures designed to evaluate interpersonal behavior and personality characteristics. Participants’ responses are transformed into quantitative scores representing interpersonal dimensions and behavioral patterns that characterize the individual’s typical interactions with others.

Psychometric evaluation typically includes analyses of internal consistency using Cronbach’s alpha coefficient, together with assessments of test–retest reliability, construct validity, content validity, criterion validity, convergent validity, discriminant validity, and exploratory and confirmatory factor analyses (EFA/CFA) to verify the theoretical structure of the instrument. Additional analyses may include composite reliability, measurement invariance across demographic groups, and item-response analyses to ensure robust psychometric performance.

Statistical procedures commonly include descriptive statistics, calculation of means and standard deviations, Pearson or Spearman correlation analyses, multiple regression models, hierarchical regression, structural equation modeling (SEM), cluster analysis, latent profile analysis, mediation and moderation analyses, and comparative analyses such as independent-samples t-tests and analysis of variance (ANOVA). These approaches enable researchers to investigate associations between interpersonal behavior and variables such as personality traits, attachment style, emotional intelligence, anxiety, depression, psychological distress, relationship satisfaction, occupational functioning, leadership style, and overall mental health.

The findings are particularly valuable in psychological assessment, psychotherapy, psychiatric evaluation, counseling, educational settings, organizational consulting, and personality research. They support clinicians and researchers in identifying dysfunctional interpersonal patterns, monitoring therapeutic progress, evaluating intervention effectiveness, and developing individualized treatment plans aimed at improving interpersonal functioning and psychosocial adjustment.

Objective

The primary objective of the Interpersonal Check List (ICL-128) is to provide a reliable and valid assessment of individuals’ interpersonal behaviors, relationship patterns, and personality characteristics that influence social interaction. The questionnaire enables psychologists, psychiatrists, counselors, researchers, and other mental health professionals to identify characteristic interpersonal styles, understand how individuals relate to others, and evaluate the emotional and behavioral processes underlying interpersonal functioning.

The instrument also facilitates the investigation of interpersonal dynamics associated with psychological adjustment, relationship quality, communication effectiveness, and personality functioning. Furthermore, it supports clinical diagnosis, psychotherapy planning, outcome evaluation, and research examining the interpersonal determinants of mental health and social functioning.

Scoring

The Interpersonal Check List (ICL-128) consists of 128 self-report items, with each item rated on a 5-point Likert-type response scale, ranging from 0 (Never) to 4 (Always). Individual responses are summed to calculate total and dimension-specific scores representing the participant’s interpersonal characteristics and behavioral tendencies.

Higher scores on individual interpersonal dimensions indicate a stronger expression of the corresponding behavioral characteristics, such as friendliness, dominance, cooperation, assertiveness, dependency, hostility, or social withdrawal, depending on the specific scale being evaluated. Lower scores indicate a less pronounced expression of these interpersonal tendencies. The resulting interpersonal profile provides valuable information regarding the individual’s characteristic interaction style, emotional responses within relationships, and patterns of social functioning.

Interpretation of questionnaire scores should always be supported by comprehensive psychometric evaluation, including analyses of Cronbach’s alpha coefficients, construct validity, criterion validity, exploratory and confirmatory factor analyses, measurement invariance, normative comparisons, and cross-cultural validation, ensuring accurate and reliable assessment across diverse clinical and community populations.

References

LaForge, R., & Suczek, R. (1955). The Interpersonal Dimension of Personality: III. An Interpersonal Check List. Journal of Personality, 24, 94–112.

Leary, T. F. (1957). Interpersonal Diagnosis of Personality. New York: Ronald Press.

LaForge, R., Leary, T. F., Naboisek, H., Coffey, H., & Freedman, M. B. (1954). The Interpersonal Dimension of Personality: II. An Objective Study of Repression. Journal of Personality, 23, 129–154.

Leary, T. F., & Coffey, H. S. (1955). Interpersonal Diagnosis: Some Problems of Methodology and Validation. Journal of Abnormal and Social Psychology, 50, 110–124.