The Fort Worth Trimester Plan (Intensified Learning Plan) employes three terms of approximately 60 days, each to replace a 90-day semester. To maintain an equivalent amount of classroom time, class periods are extended to 80 minutes at the high school level. The plan was implemented at one high school and three middle schools in 1970-71. The evaluative data provided in this report were gathered primarily from the three high schools in which the trimester plan was newly implemented in 1971-72. Information was gathered from students and teachers as well as through the use of tests. Data for comparative purposes were collected from three semester schools. Evaluation focused on several concerns that emerged from the first-year assessment: academic achievement, effects of a lapsed trimester between courses, teaching styles of trimester teachers, the extent to which students chose early graduation over an extended curriculum, teacher fatigue, student attentiveness during the longer period, and overall teacher assessment of the trimester plan. Results are summarized by concerns examined. (Author/KM)