The effect of a short (3-week) winter break on elementary students with and without mild disabilities was assessed in math using three different analyses. All students participated in curriculum-based measurement (CBM) before and after the school break. These CBM data were used to assess postbreak regression with the following analyses: (a) comparison of level of performance before and after the break, and (b) comparison of pre-and postbreak slopes of progress. Results indicated that regression differed by type of analysis. Regression was not indicated when levels of comparison were examined, although levels of performance for students with and without disabilities differed significantly after the short break. When the effect of the break on students' trends of progress was compared, it was revealed that students with positive prebreak trends were affected adversely by the school break, whereas students with negative prebreak trends were not. Implications for practice and additional research are discussed.Among the many suggestions for educational reform in recent years, one frequent recommendation is the modification of the traditional 9-month calendar (Ballinger, 1987). Year-round schooling, proposed as an alternative to the current agrarian-based calendar, offers several possible benefits. These include (a) improved educational opportunities and academic achievement for typical students (Gunnerson & Hummel, 1987;Mastruzzi, 1987), bilingual students (Doyle & Finn, 1985, and students with behavior, situational, or learning problems (Gitlin, 1988); (b) decreased drop-out rates (