This is the second of two reports on the first year activities and results of the Systems Thinking and Curriculum Innovation Project (STACI), a two-year project which is examining the cognitive demands and consequences of using the STELLA (Structural Thinking Experimental Learning Laboratory with Animation) software to teach systems thinking, content knowledge, and problem solving. This report focuses on the performance of students at Brattleboro Union High School (Vermont) in physical science, biology, chemistry, and social studies on standardized and other tests; traditionally taught courses provided control. Four types of data are analyzed: (1) performance on achievement and ability tests and differences between students in traditional and systems classes within subjects; (2) performance on a reference battery of four cognitive tests and differences between subject classes; (3) performance on content-knowledge tests and the relationship between content and achievement tests; and (4) performance on systems thinking instruments, including the characteristics of the tests and the performance of students in different subject areas. Finally, interrelationships among all four types of data are examined and correlations are noted. The general effectiveness of each type of test is considered, and possible adjustments, changes, and revisions for the coming academic year are discussed. In addition, a new focus on self-regulated learning is detailed. Analyses of the data are presented in six tables within the text and five appended tables. (10 references) (EW)