<![CDATA[This study aimed to describe students’ chemistry learning experiences in senior high school and their Basic Chemistry learning outcomes, as well as to analyze differences in Basic Chemistry learning outcomes between the 2022 and 2025 cohorts and based on chemistry learning experience among 2025 cohort students in the Chemistry Education Study Program, Faculty of Teacher Training and Education, Halu Oleo University. This study employed a quantitative approach with descriptive and comparative methods using an ex post facto design. The sample consisted of 115 students, 48 from the 2022 cohort and 67 from the 2025 cohort selected through purposive sampling. Data were collected using questionnaires to capture respondents’ characteristics and chemistry learning experience in senior high school, as well as documentation of final grades in the Basic Chemistry course. Data were analyzed using descriptive statistics and the Mann-Whitney U test. The results showed that all students from the 2022 cohort had studied chemistry for three years in senior high school, whereas students from the 2025 cohort had varying chemistry learning experiences: 0-1 year, 2 years, and 3 years. Basic Chemistry learning outcomes were dominated by grade B (88 students; 76.5%), followed by grade C (25 students; 21.7%) and grade A (3 students; 2.6%). The Mann-Whitney U test indicated a significant difference in Basic Chemistry learning outcomes between the 2022 and 2025 cohorts (p < 0.05), with the 2025 cohort obtaining a higher mean rank than the 2022 cohort. Among 2025 cohort students, however, no significant difference was found in Basic Chemistry learning outcomes between students with 0-1 year and those with 2-3 years of chemistry learning experience (p > 0.05). These findings indicate that the duration of prior chemistry learning experience does not significantly differentiate students’ Basic Chemistry outcomes, whereas cohort differences are associated with significant variation in learning outcomes.]]>
