Developing an Achievement Test about 7th Grade “Solar System and Beyond” Unit: Analysis of Validity and Reliability

Abstract

The aim of this research is to develop a reliable and valid achievement test to measure academic success of pupils about 7th grade’s “Solar System and Beyond” unit. For this reason, depending on the objectives of “Solar System and Beyond” unit, which is included in middle school science program, which was published in 2018, 42 multiple-choice test questions were prepared. The clearness of the test questions, cohesion with the objectives and scientific knowledge were designed with the care of various sights of the authorities in teaching science field which depend on the technic which was suggested by Lawshe (1975). According to this, content validity score was calculated as .94. The pilot study for this test put into practice with 254 students who had studied 7th grade in 2018-2019 academic years. As a consequence of the item statistic which was realized in the process of test development by the answers of the students for each question, difficulty score and item discrimination were calculated for each of the item. As a consequence of item statistic, 8 items were excluded from the test and the last form of the “Solar System and Beyond Academic Achievement Test” was designed with 35 questions. As a result of the analysis, the last form’s KR-20 reliability co-efficient was calculated as .87. Average item difficulty index was calculated as .61 and average item discrimination index was calculated as .48. According to this outcome, average item difficulty was identified as midlevel, and average item discrimination was identified as high-level.