IA (individual adaptability), COFL (cognitive flexibility), PNS (personal need for structure), and rigidity of attitudes, all have an aim in common to evaluate the person's self-perceived capacity to manifest a flexible or inflexible behavior in a given situation. However, these seemingly related concepts have rarely been investigated jointly. The goal of the present research is twofold: (1) to explore elements of discriminate and convergent validity of IA by relating it to COFL, PNS, and rigidity; and (2) to examine individual differences regarding gender, educational attainment, and labor force status in regards to the previously mentioned concepts. The results suggest that these concepts are related but remain distinct constructs, and that they differ in their capacity to differentiate between individuals based on gender, education, and labor force status.