IOSR Journal of Research & Method in Education (IOSR-JRME) e-ISSN: 2320–1959.p- ISSN: 2320–1940 Volume 10, Issue 2 Ser. I. (Mar. - Apr.2020), PP 18-24 www.iosrjournals.org DOI: 10.9790/7388-1002011824 www.iosrjournals.org 18 | Page Meta-Analysis of Studies on Effects of Instructional Approaches on Students’ Academic Achievement in Chemistry EKE, Joy Anulika 1 , Prof. Okeke, O.C.Sam 2 1. Department of Science Education, NnamdiAzikiwe University, Awka, Anambra State 2. Department of Science Education, NnamdiAzikiwe University, Awka, Anambra State Abstract: The focused on the meta-analysis of studies on effects of instructional approaches on students’ academic achievement in chemistry. The study performed a meta-analysis of results from the experimental studies that examined the effect of teaching method/ strategies on academic achievement in chemistry, so as to arrive at the approach that had largest effect. size. Three research questions and five hypotheses guided this study. Ex post facto design was adopted for the study. Government owned universities in South East of Nigeria that offer chemistry in the Department of Science Education were used for the studies .The population of the study consisted of all unpublished previous studies on effect of teaching methods/ strategies on students’ achievement in chemistry. A sample of 44 studies with 45 approaches carried out in Nigeria between 2000 to 2018 purposively drawn from four universities was used for this study. The random effects model was adopted. Descriptive statistics, statistical transformations and effect sizes were used to analyze the data for the research questions while the Winer combined test was used to test the hypotheses at 0.05 levels of significance. The findings of the study showed that the overall mean effect of instructional approaches on students’ achievement in chemistry are respectively significant at 0.05 levels. The findings also revealed that meta-cognitive instructional strategies (MIS-0.730), computer Aided instruction (CAI-0.715), inquiry based teaching methods(IBTM-0.650), and cooperative learning (CL- 0.620) had large effect sizes but meta-cognitive instructional strategies (MIS) has the largest effect size on achievement. Based on the findings of the study, it was recommended among others that students in teacher training institutions and the already serving teachers should be trained in the approach of using metacognitive instructional strategies in teaching chemistry through seminars, workshops, conferences and in-service programmes. Keywords: meta-analysis, effect size, achievement, chemistry, instructional approach --------------------------------------------------------------------------------------------------------------------------------------- Date of Submission: 24-02-2020 Date of Acceptance: 07-03-2020 --------------------------------------------------------------------------------------------------------------------------------------- I. Introduction Chemistry is one of disciplines through which the educational objectives are to be achieved. It is the science that systematically studies composition, properties and activities of organic and inorganic substances and various elementary forms of matter (Nnoli, 2011). Chemistry plays a vital role in the future progress of mankind and nation. According to the Nigerian Educational Research and Development Council (NERDC, 2007), it is very important for effective living in modern age of science and technology. Given its application in industries, and in many other professions, the minimum standard embodied in chemistry education is designed to build confidence in students and enhance their abilities to adapt to the changing situation in scientific and technologically oriented society. Based on these important issues, students are expected to manifest high level of achievement in the subject yet, Onwukwe (2011) noted that students do not achieve well as they should in chemistry. Researchers however, have been undaunted in their quest to finding a lasting solution to the problem. These effort led the researchers to investigate various teaching methods/ strategies on students academic achievement to determine the methods that enhance achievement most. Notwithstanding various findings and recommendations given by researchers, chemistry teachers have not found it easy to select and apply most effective teaching method for success of their students because most of the methods experimented upon proved to be significant and some not statistically significant. Additionally, their significance varied in magnitude and direction that one cannot easily say the degree of their effectiveness. Example, studies on guided inquiry by Odukwe (2018), concept mapping by Ikokwu (2015), self-regulated learning by Loong (2016), computer assisted instruction by Okwuduba (2016), cooperative learning by Izuegbuna(2018) among others indicated significant effects on students’ achievement . These researchers’ reports show some conflicting results in magnitude and direction in their effect size. Even, findings from replications of studies show some inconsistencies. The most distressing thing is that one cannot categorically state the extent of the effect of each teaching method in enhancing students' interest