Abstract
This study investigates the impact of staff development programmes on teachers’ effectiveness in public secondary schools in Kachia Local Government Area of Kaduna State, Nigeria. Employing a descriptive research design, the study’s population comprises 2,450 teachers and school administrators. A sample size of 384 was determined using Krejcie and Morgan’s (1970) formula, ensuring representativeness for large populations. Participants were selected through simple random sampling, reducing selection bias and enhancing the generalization of the results. The research instrument demonstrated strong validity (0.79) and reliability (0.77), confirming its accuracy and consistency. Data were analyzed using mean and standard deviation for answering research questions, with a 2.50 benchmark on a Likert scale. Hypotheses were tested using chi-square to evaluate relationships between variables such as in-service training, workshop attendance, mentoring, and teacher effectiveness. The findings indicate a significant influence of regular in-service training, workshop participation, and mentoring programmes on teachers’ classroom performance, lesson delivery, and student engagement. The study concludes that staff development programmes play a crucial role in enhancing teachers’ effectiveness in public secondary schools in Kachia LGA. These findings underscore the need for consistent and well-planned staff development initiatives to improve instructional quality and student outcomes in the region.