DEFINITIONSA type of analysis used to assesswhether items on a scale aretapping the same construct andare sufficiently discriminating.(Pollit & Beck)
The procedure used judge the qualityof an item (Neeraja)Item analysis is the process oflooking at the item responses of atest
PURPOSES Select best questions Identify structural content defect inquestion Detect learning difficulties Identify weakness Interpretation of student’sperformance
Understand behavior of item To become better competentteachers. Control the quality of a test. Evaluate the students.
Point out problems of validity test byrevising and eliminating ineffectiveitems Find out performance of group Reveals the facility value of each ofthe item and the discrimination.
ITEM DIFFICULTY:It is measured by calculating thepercentage of test-takers whoanswer the item correctly
ITEM DIFFICULTY INDEXP=R/N X 100R - No of pupil who answered theitem correctlyN - Total No of pupil who tried them
DIFFICULTY LEVEL=Average on the test X 100Max. Possible scoreDIFFICULTY INDEX =H+L X 100NH -No. of correct answers to the high groupL - No. of correct answers to the low groupN - Total No. of students in both group
FACILITY VALUE=No. of students answeringquestion correctly X100No. of students who have taken the test
ITEM DISCRIMINATION: The way anitem differentiates students who knowthe content from who do not know
DISCRIMINATION INDEXThe degree to which a given itemdiscriminates among students whodiffer sharply in the functionsmeasured by the test as a whole
DISCRIMINATION INDEXFormulaDI=2 x (H-L)NH – Number of correct answer in high groupL - Number of correct answer in low groupN – Total number of students in bothgroups
DISTRACTOR EVALUATION: Inaddition to evaluation of correctanswers to an item distracters orwrong answers also individuallyevaluated
INTER-ITEM CORRELATION This matrix displays thecorrelation of each item withevery other item. This matrix provides importantinformation about a test’sinternal consistency, and whatcould be done to improve it.
ITEM-TOTAL CORRELATIONS Point-biserial or item-totalcorrelations assess the usefulness ofan item as a measure of individualdifferences in knowledge, ability, orpersonality characteristic. Here each test item (incorrect = 0;correct =1) is correlated with theperson’s total test score.
ITEM REVISION Developing a valid and reliabletest is an ongoing process.It helps the faculty to recall itemsand student responses to them.Item revision should conductafter item analysis.
STEPS OF ITEM ANALYSIS After the test is scored, arrange thetest scores in rank order fromhighest to lowest. Divide the score into a high scoringhalf and a low scoring half For each item, tally the number ofstudents in each group who choseeach alternative. Record thesecounts on a copy of test item next toeach response item.
Calculate the difficulty index for eachitem. Calculate the discrimination index foreach item. Check each items for implausibledistracters, ambiguity and mis-keying.
USING ITEM ANALYSIS RESULT judge the worth or quality of a test. Aids in subsequent test revision Increase skills in test construction Planning future activities. Basis for discussing test result Promotion of students to the next highergrade improve teaching methods and techniques