The Investment Model of Relationship Commitment: Factor Analysis, Reliability, and Validity

The investment model depicts the theory of interdependence and uses interconnected structures to analyze the tendency to maintain a relationship. The aim of this study was to examine the factor structure, reliability and validity of the scale of the investment model of relationship commitment among couples in Tehran.
Material and This study was a descriptive study with correlation design. Participants included couples with middle-aged children in Tehran. Cluster random sampling method was used in the study. Data were collected via the investment model of relationship commitment questionnaire which was developed by Rusbult. To validate the questionnaire, construct validity, confimatory factor analysis, and convergent validity were used. To test the reliability of the questionnaire, Cronbach’s alpha and retest reliability coeffiient were used.
Responses of 420 participants, 250 women and 170 men, were analyzed. The Cronbach’s alpha coeffiient was 0.97 for satisfaction subscales, 0.87 the quality of the alternatives, 0.85 the investment in the relationship, and 0.67 the marital commitment. Test re-test coeffiient in a two-week interval was 0.94 for the subscales of satisfaction, 0.86 the quality of the alternatives, 0.82 the investment rate, and 0.67 the personal commitment. Correlation coeffiients showed that marital adjustment scale had a signifiant correlation of 0.84 with satisfaction subscales, 0.29 substitute quality, 0.55 investment rate, and 0.77 personal commitment, which indicates a convergent validity, P The confimatory factor structure, reliability and validity of the investment model of relationship commitment were acceptable for research and diagnostic applications.