<p>This dissertation investigated an affective curriculum intervention’s effectiveness in resolving</p><p>underachievement. The intervention was first implemented at a summer program with 20 students</p><p>and four camp counselors. Inductive analysis of qualitative data indicated that most participants</p><p>had positive perceptions of the model. Descriptive analyses indicated the intervention had small,</p><p>positive effects on students’ academic self-perceptions (MD = 0.122, SD = 0.621, d = 0.196) and</p><p>attitudes toward teachers (MD = 0.139, SD = 0.848, d = 0.164) were found. There was no change</p><p>in attitudes toward school (MD = 0.080, SD = 1.327, d = 0.060) and goal valuation (MD = 0, SD =</p><p>0.721, d = 0) and a moderate, negative effect on self-regulation (MD = -0.620, SD = 1.346, d = -</p><p>0.460). The intervention was then implemented in a middle school with one 12-year old girl who</p><p>was gifted and underachieving. An explanatory mixed methods design, combining a single-case</p><p>A-B design, an interrupted time series simulation, and inductive analysis, was used. The model</p><p>was perceived as useful, mainly in increasing self-perceptions. Results showed a significant</p><p>increase in behavioral engagement (d = 1.224, p <.001) and improved achievement (SMD = 1.28).</p><p>Academic self-perception (MD = 0.57) and attitudes toward school (MD = 1.00) improved,</p><p>attitudes toward teachers showed no change, and goal valuation (MD = -0.67) and self-regulation</p><p>(MD = -0.40) decreased. These two studies provide preliminary evidence for the effectiveness of</p><p>the intervention.</p>