Abstract This study aims at determining: (a) whether there is any difference between chemistry learning achievements of students taking the chemistry class with the implementation of Performance Assessment and ones joining the class without the implementation of Performance Assessment if the prior knowledge was statistically controlled, (b) Differences of scores in male and females' students after the implementation of performance assessment and traditional assessment in class. The experiment was conducted in 2 high schools in Malayer. The subjects were 92 pre-university science students (46 boys and 46 girls) that were selected from population through random, multi-step and cluster sampling methods and then randomly assign patterns to experimental group and control group. Research instruments used included academic achievement pretest and post test that was prepared by researcher and teachers. The results have provided sufficient evidence for the context validity of these two instruments. Cronbach coefficient alpha reliability of chemistry academic achievement pre test was .81 and post test was .83. Two- factor covariance analysis method (ANCOVA) was utilized for data analysis. The results showed: (a) there were significant differences on chemistry learning achievement with and without the implementation of Performance Assessment on pre-university chemistry students. (b) Based on the statistical analysis of ANCOVA of same subjects, it showed that there was a significant increase of scores of females' students to learn chemistry in classes with the implementation Performance Assessment. [Omidi M, Sridhar Y.N., Azizmalayeri K, Effectiveness of Assessment patterns in chemistry Learning. Life Sci J 2012;9(3):1979-1982]. (ISSN: 1097-8135). http://www.lifesciencesite.com. 285
