The Investment Model Scale: Measuring commitment level, satisfaction level, quality of alternatives, and investment size

Three studies evaluated the reliability and validity of the Investment Mode l Scale, an instrument designed to measure four constructs, including commi tment level and three bases of dependence-satisfaction level, quality of al ternatives and investment size. In all three studies, reliability analyses revealed good internal consistency among items designed to measure each con struct. Also, principal components analyses performed on scale items reveal ed evidence of four factors, with items designed to measure each construct loading on independent factors. Studies 2 and 3 examined associations of mo del variables with instruments measuring diverse qualities of relationships and assorted personal dispositions. As anticipated, Investment Model varia bles were moderately associated with other measures reflecting superior cou ple functioning (e.g., dyadic adjustment, trust level, inclusion of other i n the self), and were essentially unrelated to measures assessing personal dispositions (e.g., need for cognition, self-esteem). In addition, Study 3 demonstrated that earlier measures of Investment Model variables predicted later levels of dyadic adjustment and later relationship status (persisted vs. ended). It is hoped that the existence of a reliable and valid Investme nt Model Scale will promote further research regarding commitment and inter dependence in ongoing close relationships.