Date of Award


Document Type

Open Access Dissertation



First Advisor

Bradley H. Smith


This study examined the overall efficacy and treatment fidelity of a semester long after school intervention aimed at improving middle school students’ overall academic achievement, subjective well-being (SWB), gratitude, and self-efficacy. Participants in the study included 6th to 8th grade students from two public middle schools in South Carolina. Upon registration for the after school program, students were randomly assigned to one of two conditions: (1) the Leadership and Young Professionals (LYP) treatment group or (2) the wait list control group who received intervention during the following school semester. Both subjective (self-report) and objective measures were collected on participants at two time points during the semester (i.e., at baseline and end of Quarter 2 grading period). Self-report measures included students’ levels of life satisfaction, gratitude, self-efficacy, and frequency of positive and negative affect. Objective measures of the study consisted of students’ school grades and after-school performance. After checking distributional assumptions, inferential statistics were used to assess group differences. The General Linear Model (GLM) was used for data with two time points with pre-test scores as covariates. To help visualize change and effect sizes, group means with 80% confidence intervals are graphed, and overall effect size calculations using adjusted Cohen’s d to evaluate baseline to post-test group differences are presented. On self-report measures, significant main effects were found on SWB, gratitude, self-efficacy and teacher-student relationships with effect sizes (adjusted Cohen’s d) ranging from 0.10 to 1.27 with an average of 0.56. On objective measures, test results were mixed with significantly positive effects of the LYP treatment group on counselor-rated after school performance, with effect sizes ranging from 0.72 to 0.75 and negative effects on school grades for Math and English with null effects on Science and Social Studies. The current study provides further support for the overall efficacy of the LYP as a multi-modal positive psychology (MMPP) intervention to enhance adolescents’ academic and social-emotional outcomes.