Discriminating Power Difficulty Item

refers to extent to which the results of an evaluation procedure serve the particular uses for which they are intended. In thi s research the researcher adopts Anderson, Herr, and Nihlen’s criteria that mention that validity of action research including democratic validity, outcome validity, process validity, catalytic validity, and dialogic validity. 12 In this research she uses three kinds of validity are outcome, process, and dialogic validity. First, outcome validity requires that the action emerging from a particular research leads to the successful resolution of the problem that was being studied, that is, your research can be considered valid of you learn something that can be applied to the subsequent research cycle. 13 Second, process validity is “the validity that requires a research has been conducted in a “dependable” and competent“manner”. 14 The last, dialogic validity; “it involves having a critical conversation with peers about research finding and practices.” 15 It could be concluded from the explanation above that we could be seen the outcome validity from the students’ result of the test. Moreover, in process validity the researcher notes all events happening during the CAR. Therefore, in these validities the research is said successful if the result of cycle II is better than cycle 1. Besides, if there might have some mistakes in the method of teaching, so the researcher should discuss this problem with the teacher to modify the further strategies. Then, for dialogic validity, to avoid invalid data the researcher and the teacher discuss and assess the students’ test result of two cycles.

2. Discriminating Power

The analysis of discriminating power of test items is to know the performance of the test through distinguishing students who have high 12 Geoffrey E.Mills, Action Research: A Guide for the Teacher Researcher, New Jersey: Merril Prentice Hall, 2003, p. 84. 13 Geoffrey E.Mills, Action Research: A Guide for the Teacher Researcher, … p. 84. 14 Geoffrey E.Mills, Action Research: A Guide for the Teacher Researcher, …p. 84. 15 Geoffrey E.Mills, Action Research: A Guide for the Teacher Researcher, New Jersey: Merril Prentice Hall, 2003, p. 85. achievement and low achievement. Discriminating power provides a more detailed analysis of the test items than does item difficulty, because it shows how the top scores and lower scores performed on each item. 16 The computing of discriminating power uses the formula as following: 17 U – L D = ──── N In which, D : The index of discriminating power U : The number of pupils in the upper group who answered the item correctly L : The number of pupils in the lower group who answered the item correctly N : Number of pupils in each of the groups Next, the discriminating scale uses: 18 DP REMARK 0.6 – 1.0 Very good 0.4 – 0.6 Good 0.1 – 0.3 Ok -1 – 0.0 Bad

3. Difficulty Item

The difficulty item analysis concerns with the proportion of comparing students who answer correctly with all of students who follow the test. Item difficulty is how easy or difficult an item is form the viewpoint of the group 16 Kathleen M. Bailey, Learning about Language Assessment: Dillemas, Decisions, and Direction, London: Heinle Heinle Publisher, 1998, p. 135. 17 Wilmar Tinambunan, Evaluation of Student Achievement, Jakarta: Depdiknas, 1998, p. 139. 18 J. B. Heaton, Classroom Testing, New York: Longman Inc, 1990, p. 174. of students or examinees taking the test of which that item is a part. The formula as following: 19 R P = ── T In which, P : Index of difficulty R : The total number of students who selected the correct answer T : The total number of students including upper and lower group

N. Criteria of the Action Success