Research in Science & Technological Education Vol. 24, No. 1, May 2006, pp. 129–138 ISSN 0263-5143 (print)/ISSN 1470-1138 (online)/06/010129–10 © 2006 Taylor & Francis DOI: 10.1080/02635140500485498 Students’ achievement in relation to reasoning ability, prior knowledge and gender Ayse Yenilmez, Semra Sungur* and Ceren Tekkaya Middle East Technical University, Turkey Taylor and Francis Ltd CRST_A_148532.sgm 10.1080/02635140500485498 Research in Science & Technological Education 0263-5143 (print)/1470-1138 (online) Original Article 2006 Taylor & Francis 24 1 000000May 2006 SemraSungur ssungur@metu.edu.tr This study investigated students’ achievement regarding photosynthesis and respiration in plants in relation to reasoning ability, prior knowledge and gender. A total of 117 eighth-grade students participated in the study. Test of logical thinking and the two-tier multiple choice tests were admin- istered to determine students’ reasoning ability and achievement, respectively. An analysis of cova- riance (ANCOVA) was conducted to assess the effect of reasoning ability on students’ achievement. The independent variable was the reasoning ability (low, medium, high), the dependent variable was the scores on the two-tier test. Students’ grades in science in previous year were used as a covariate. Analysis revealed a statistically significant mean difference between students at high and low formal levels with respect to achievement. Stepwise multiple regression analysis revealed that reasoning ability, prior knowledge and gender were significant predictors of students’ achievement in photosynthesis and respiration in plants, explaining 42% of the variance. Introduction The relationship between prior knowledge, reasoning ability, achievement and gender has received special attention in science education research for many years (Lawson & Thompson 1988; Cavallo, 1996; Valanides, 1997; Johnson & Lawson, 1998; Dimitrov, 1999; Jones et al., 2000; Lawson et al., 2000; Hupper et al., 2002; Oliva, 2003; Cavallo et al., 2003; 2004; Atkinson, 2004; Boujaude et al., 2004). These studies have reported the importance of these variables in students’ under- standing of different science concepts. For example, Cavallo (1996) investigated the relationships between tenth-grade students’ reasoning ability and their under- standing of genetic topics. She found that reasoning ability best predicted students’ achievement in solving genetics problems. Sungur and Tekkaya (2003) explored * Corresponding author. Middle East Technical University, Faculty of Education, Department of Elementary Education, 06531-Ankara, Turkey. Email: ssungur@metu.edu.tr