Post on 16-Dec-2014
description
ITEM ANALYSIS AND
VALIDATIONReported by:AGUSTIN, Levin Jasper A.BSE – E – 3 (Irreg.)
Draft subjected to Item Analysis and
Validation
PHASES
(1) try-out phase(2) Item analysis phase (level of difficulty)(3) Item revision phase
ITEM ANALYSIS
Two important characteristics:
(a)item difficulty(b)discrimination index
Item difficulty = number of students with correct answer/ total number of students
The item difficulty is usually expressed in percentage.
Range of Difficulty Index
Interpretation Action
0 – 0.25
0.26 – 0.75
0.76 – above
Difficult
Right difficulty
Easy
Revise or discard
Retain
Revise or discard
Index of Discrimination
Tells whether it can discriminate between those who do not know the answer
Difficulty in: Upper 25% of the class Lower 25% of the class
Formula: DU - DL
Index Range Interpretation Action
-1.0 - -.50
-.55 – 0.45
0.46 – 1.0
Can discriminate but
item is questionable
Non-discriminating
Discriminating item
Discard
Revise
Include
Index of Difficulty the proportion of the total group who
got the item wrong
FORMULA:
P = RU + RL X 100T
RU – The number in the upper group who
answered the item correctly
RL – The number in the lower group who
answered the item correctly
T – The total number who tried the item
VALIDATIONPURPOSE: to determine the characteristics of the whole test itself, namely, the validity and reliability of the test
VALIDITY - Is the extent to which a test measure or as referring to the appropriateness, correctness, meaningfulness and usefulness of the specific decisions a teacher makes based on the test results
Three Main Types of Evidence that may be collected:
Content-related evidence of validity
Criterion-related evidence of validity
Construct-related evidence of validity
Expectancy Table
GRADE POINT AVERAGE
Test Score
High
Average
Low
Very Good
20
10
1
Good
10
25
10
Needs Improveme
nt
5
5
14
RELIABILITY
refers to the consistency of the scores obtained
RELIABILITY INTERPRETATION
.90 and aboveExcellent reliability; at the level of the best standardized tests
.80 - .90Very good for a classroom test.
.70 - .80Good for a classroom test; in the range of most. There are probably a few items which could be improved.
.60 - .70
Somewhat low. This test needs to be supplemented by other measures (e.g., more tests) to determine grades. There are probably some items which could be improved.
.50 - .60
Suggests need for revision of test; unless it is quite short (ten or fewer items). The test definitely needs to be supplemented by other measures (e.g., more tests) for grafing
.50 or belowQuestionable reliability. This test should not contribute heavily to the course grade, and it needs revision.