A modern ninth grade algebra curriculum, developed by the School Mathematics Study Group (SMSG), was evaluated in 21 classrooms using the SMSG curriculum and 23 classrooms using the traditional algebra curriculum. Near the end of the school year, both groups were administered a test constructed for the SMSG course, and the Cooperative Algebra Test, a traditional algebra achievement test. Results indicated that SMSG classes had a significantly higher mean score than the traditional classes. In addition, the traditional classes had a significantly higher mean score on the traditional test than did the SMSG classes. Of factors affecting selection of the best curriculum, two were considered: (1) the manner in which the textbook presented a topic; and (2) achievement on items related to that topic. The specific topic was transitive relations (if A=B and B=C, then A=C). The SMSG textbook covered both equalities and inequalities and encouraged the use of graphic representations to solve problems, more so than the traditional texts. The SMSG test contained more items on this topic, and SMSG students performed better on these problems. However, the one item involving transitive relations on the traditional test was answered correctly by more students from traditional classes. It appeared that the SMSG course did a better job of developing abilities to solve these problems than the traditional course. Paper presented at ASCD, St. Louis, March 11, 1963.