Effects of Advance Organizers on Students’ Achievement in Biology in Secondary Schools in Kilifi County, Kenya

<p><em>This study investigated the effects of using advance organizers on students’ achievement in biology in secondary schools in Kilifi County. </em><em>Solomon Four, Non-Equivalent control group design was used in this study. The study targeted all secondary school students in Kilifi County. The accessible population consisted of all form two students in Kilifi County. Purposive sampling was used to select four co-educational secondary schools in Kilifi County. The four schools were randomly assigned to experimental groups (E₁) and (E₂) and control groups C₁ and C₂. A total of 156 students participated in the study. Data was collected using Biology Achievement Test (BAT). The reliability of BAT was estimated using Kuder-Richardson (K-R) 20 and Cronbach’s coefficient. This yielded a reliability coefficient of 0.82 and 0.79 respectively. BAT was validated by experts in science education from Egerton University. The data collected was analyzed using mean, </em><em>o</em><em>ne-way ANOVA and t</em><em>-</em><em>test. The level of significance was 0.05. The findings of this study show that there was statistically significant difference in achievement between learners in favour of those taught using advance organizers compared to those taught using conventional teaching methods. The findings also indicate that there was no statistically significant gender difference in achievement.</em><em></em></p>