Kamau, Njeri Anne2025-09-012025-09-012025-04https://ir-library.ku.ac.ke/handle/123456789/31327A research thesis submitted in partial fulfilment of the requirements for the award of the degree of doctor of philosophy (educational psychology) in The School of Education and Lifelong Learning of Kenyatta University, April 2025 Supervisors: Prof. Theresia K. Kinai Dr. Doyne K. MugambiSince 2017, most secondary school students in Nyandarua County have been performing below average in Kenya Certificate of Secondary Education. Reviewed studies have largely attributed the academic underachievement to school environmental factors like leadership, pedagogy and insufficient resources. Few studies have investigated how students’ motivational constructs and school adjustment relate to academic achievement. This study examined the relationships among dispositional optimism, coping strategies, school adjustment, and academic achievement. How these variables differ by type of school was also investigated. Further, a model for predicting academic achievement from dispositional optimism, coping strategies and school adjustment was tested. Guided by Eccles et al.’s expectancy-value theory (1983) and Eccles and Midgley’s stage-environment fit theory (1989), this study used a convergent mixed methods research design. The study targeted 16,813 form two learners in 173 public secondary schools in Nyandarua County, Kenya. The county, the public schools and the form two class were all purposefully sampled. Based on the sub counties and types of schools, a stratified proportionate sample of 10 secondary schools was obtained. In these schools, 391 students were selected through simple random sampling. The validity and reliability of the study instruments was ascertained in a pilot study involving 40 form two students in a co-educational public secondary school in Nyandarua County. Quantitative data were collected using a self-reported questionnaire comprising of items from the Life Orientation Test-Revised, brief COPE Inventory and School Adjustment Inventory. Students’ academic achievement scores were obtained from school academic records. Qualitative data were collected through a semi-structured interview schedule. Using SPSS, quantitative data were analyzed descriptively and inferentially. Qualitative data were analysed thematically as per the objectives of the study. The results indicated a significant positive correlation (r (376) = .46, p = .00) between dispositional optimism and academic achievement. There was also a significant positive correlation (r (376) = .33, p = .01) between coping strategies and academic achievement. Likewise, the correlation between school adjustment and academic achievement was positive and significant, (r (376) = .13, p = .01). There were significant school type differences in dispositional optimism (F (3,374) = 66.13, p = .00, η2 = .35), coping strategies (F (3,374) = 63.23, p = .00, η2 = .34) and school adjustment (F (3,374) = 56.25, p = .00, η2 = .31) respectively, in favour of boys’ boarding school. The differences had moderate effect sizes. The predictive equation for academic achievement was significant (F (3,374) = 50.89, p = .00) as well as the model involving school type as an intervening variable (F (4,373) = 54.17, p = .00). Of the three predictor variables, coping strategies seemed to have direct effects on the rest of study variables. The results of the current study demonstrated that the three predictor variables, dispositional optimism, coping strategies and school adjustment positively and significantly predicted academic achievement. The study recommends that teachers and parents should equip learners with effective coping strategies as well as cultivate higher levels of optimism and school adjustment in efforts aimed at improving academic achievement among secondary school students in Nyandarua County and beyondenThesis