Diagnosing the Diagnostics: Misconceptions of Twelfth Grade Students on Selected Chemistry Concepts in Two Preparatory Schools in Eastern Ethiopia

This article aimed at diagnosing suspected students’ misconceptions towards the selected five chemistry concepts (valence, oxidation number, coordination number, number of bonds and formal charge) by developing appropriate diagnostic instrument. Within this theme, it was also attempted to test the accuracy and precision of the common diagnostic tests in measuring students’ misconceptions and performance in terms of different test standards and standard indicators. To attain these goals, respective data were gathered through open-ended test and three-tier chemistry misconception test. The earlier was administered to identify major areas of students’ misconceptions, while the later was administered twice as a pilot and revised form. Using the result of the pilot test some items were rewritten accordingly. The result of the study showed that conceptual knowledge gained by these students was only superficial, accompanied by a range of misconceptions largely shared by about 28 % of the sampled students. Finally, the findings of this study show that open-ended multiple choice items and two-tier tests are less valid, reliable and discriminatory than that of three-tier chemistry misconceptions test.