Motivation orientation research consistently finds two factors, Performance and Learning, that overlap substantially with other factors coming from different theoretical perspectives of motivation. Similar to related work in the Big-Five Theory of Personality, researchers posited a Big-Two-Factor Theory of motivation orientation and evaluated the implicit assumption that selected motivation constructs can be represented as higher-order Performance and Learning factors. They collected test-retest data (multi-item scales designed to measure eight motivational constructs) from elementary school students. Confirmatory factor analyses (CFAs) provided good support for each of the eight scales. Higher order CFA models fit the data reasonably well for each time considered separately and the well-defined, higher-order Learning and Performance factors. For combined pretest/posttest data, the substantial test-retest correlations for first-order factors were not adequately explained by higher order factors. A multi-cohort, multi-occasion analysis of mean differences showed strictly linear declines that were smaller for Learning-related scales than Performance-related scales. While results supported the Big-Two-Factor Theory, there was considerable variance in each of the eight scales that was reliable at any one time and stable over time but unexplained by the higher-order factors. (Contains 72 references.) (SM)