A new steady-state interaction measure, the relative interaction array (RIA), is explored in terms of its features, properties, and relationship to the relative gain array (RGA). It is demonstrated that the RIA offers a better measure of individual interactions than the RGA. Moreover, it is shown that the RIA also contains direct information about closed stability, integrity, and robustness. Taking advantage of its definiteness in measuring the amount of loop interaction by its size, the RIA is further extended to propose a new overall interaction measure which is able to avoid ambiguities associated with the RGA pairing criteria and to overcome problems associated with other overall interaction measures. Interestingly, the RIA-based overall interaction measure leads to a "corrected" version of the intuitive RGA-based one. The final RIA-based pairing criteria provide a comprehensive and reliable solution to the selection of the best variable pairing and thus represent a promising tool. Also, variable pairing criteria on the basis of interaction measurement, stability, and integrity as well as robustness considerations are systematically addressed with new insights provided.