Some issues related to the use of justifications to multiple-choice answers

In recent years there has been a growing interest in misconceptions which are prevalent among students and in ways and means which can be used to identify these misconceptions. The present study focuses on the use of justifications to multiple-choice items. This approach has been employed for several years in the biology matriculation tests in Israel and found to be a very effective diagnostic tool. Two specific questions were studied: 1. To what extent will the justifications differ if the correct answer is made known to the students so that they can concentrate on the justifications without being bothered by the need to search for the best answer. 2. Since in the case described in 1 above the correct answer is made known perhaps the distractors are altogether unnecessary? Two samples were studied. The first comprised 114 10th and 11th grade (15/16-year old) students who studied biology in the year 1987 in seven high schools in California. The second consisted of 350 Israeli 12th grade (17-year old) stud...