This extension of Harris' classification system permits classification of the interval-scale properties of any 2 x 2 (two person, two choice) game. The system is compared to taxonomies developed by various previous researchers. It is shown to permit compact description of any 2 x 2 game as an octet of numbers. It also permits rapid classification of comparisons among game matrices with respect to the strength of measurement which must be assumed for the comparison to be meaningful. (Author/CK)