This paper discusses the effect of Frayer model and Think – Pair – Share as Target Methods of assessment on prospective science teachers’ academic achievement in the course of Curriculum Development. Student’s learning outcomes were targeted and only those areas were covered that may be assessed through Frayer Model and Think – Pair – Share. Literature however is lacking in how these two assessment methods improve achievement and this study was conducted to address this research gap. The study carried quasi-experimental design of pre-test post-test. The sample was comprised of prospective science teachers studying the core course of Curriculum Development in a public sector university of district Lahore (Pakistan) and was divided into two groups - experimental group and control group with sample size of 51 and 36 students respectively. Pretest was taken from both the groups before exposing them to the treatment. Pretest and posttest were developed in the light of basic rules/principles of test construction and Bloom’s Taxonomy of Educational Objectives. Validity of the test was ensured by three assessment and two research experts. The reliability of the test was ensured through conducting psychometric analysis on 200 students. The reliability of the final test 0.832 and the items selected having range of item difficulty between 0.2 – 0.8 and discrimination index 0.2 – 0.6. Treatment was carefully applied at the different intervals and the whole plan of experiment was validated by research experts. After treatment posttest was taken from both the groups to measure the effect of treatment on academic achievement. Results revealed that students who were assessed through Target methods of assessment showed better results as compared to the students received no treatment. Results showed that students showed better performance when they were assessed through Think – Pair – Share as compared to Frayer Model. On the basis of results, it was recommended to use Target assessment methods (Frayer model and Think – Pair – Share in the classrooms to improve the students’ academic achievement and for future researchers it was recommended to use diverse methods of assessment in different subjects and across various levels to check the effectiveness of assessment methods.