Definition of Item Analysis

As a quote, from Lyle F. Ba chman, states that, “to conduct an item analysis, we first arrange the scored test papers or answer sheets in order from the highest score to the lowest score. Next, we separate the papers into upper and lower groups, according to their total test scores. For large groups, we would choose the upper and lower 27 percent, while for smaller groups, we would typically choose the upper and lower one-third. ” 89 The formula used for analyzing the difficulty level of each item in large group is stated below: In which: TK : Index of difficulty U : The number of students in the upper group who answer the item correctly L : The number of students in the lower group who answer the item correctly T : The number of students in upper and lower group 90 Next, for the small group, teacher or test maker can easily evaluate an item by using all the students’ answer sheets. Then, the formula is: 89 Lyle F. Bachman, Statistical Analyses for Language Assessment, Cambridge: Cambridge University Press, 2004, p. 123. 90 M. Ngalim Purwanto, Prinsip-Prinsip dan Teknik Evaluasi Pengajaran, Bandung: Remadja Karya, 1986, p. 153. B P = JS U + L TK = T In which: P : Index of difficulty B : The total number of students who got the item correct JS : The number of students who took a test 91 The formula above is commonly used for multiple choice item. For the short-answer item, Zainal Arifin states as follows: 92 After analyzing each item and obtaining its difficulty level, the next thing to do is finding out the difficulty level for whole items in a test. It is performed by using the following formula: In which: P : Difficulty level for whole items b : Difficulty level of each item Σ : Sigma Total N : Total number of test items 93 91 Suharsimi Arikunto, Dasar-Dasar Evaluasi Pendidikan, Jakarta: PT. Bumi Aksara, 2006, p. 208. 92 Zainal Arifin, Evaluasi Pembelajaran ..., P. 135. The total of student’s score for each item Mean = The number of students Mean Index of difficulty = Maximum score of each item Σ b P = N