Page 304 - DEDU504_EDUCATIONAL_MEASUREMENT_AND_EVALUATION_ENGLISH

Educational Measurement and Evaluation

Notes The only extra care to be taken is that the number of questions of each type should be double
that of the decided one. It should also be kept in mind that some essay-type questions are such
which may only be answered by 20% students of high ability, and rest of the questions can be
answered by all students. The short-answer-type questions are such which may only be
answered by 20% students of high ability, and rest of the questions can be answered by all
students. The short-answer-type questions too are constructed in the same way. The objective-
type questions are constructed such that 27% questions can be answered by the students of
higher level only and 27% cab be answered by all.
2. Selection of Questions after Testing of Preliminary Draft : In order to know of the errors of
the test, the test is administered on some students of the required level. Then the questions are
suitably amended keeping in view the difficulties felt by the students and the suggestions
given by them, it is called preliminary try-out stage.
3. Item Analysis : It is necessary to understand the meaning of item analysis. The questions
asked in a test are called item of the test. By item analysis is meant numerical analysis of the
obtained scores of each item, the analysis of its validity and reliability, and deciding its
suitability accordingly. Item analysis is such a process by which some items are selected for
the test, some items are cancelled and some items are improved. This is done on two bases—
difficulty level of the items, and discriminating power of the items.
(a) Difficulty Level of Items : The difficulty level of a question or item is known from the
percentage of students who succeed to respond it correctly. The difficulty level of an
item indicates whether it is easy or difficult. The number of questions or items in a test
indicates the number of difficulty levels in the test independently. For selection of an
item in a test, generally, the percentage of students solving it correctly is taken into
consideration. The questions being solved correctly by all students of a group are easy in
nature, and on the opposite, the questions which are not solved by any student are
extremely difficult. Both these type of questions are not accepted in a good test. Generally,
if an item of a test is solved by 50% of the students, then it is taken to be of suitable
difficulty level. It does never mean that only those items are selected for the test which
have been solved by 50% students. Some such items too are selected which are solved by
students of higher achievement only. Generally, the items falling in the range of 30% to
70% are selected.
Finding Out Difficulty Level of the Items : All specialists are of the opinion that the
level of difficulty of an item can be found out by comparing the number of students
answering it correctly with those of answering it incorrectly. Different formulea are
used in different circumstances to find out the difficulty level of an item.
First-Method : The ratio method is the simplest method to find out the difficulty level of
an item. In this method, the ratio of the number of students answering it correctly with
the total number of the students is found out. The following formula is used to find it
out:
R
DL =
N
Here, DL = Difficulty level
R = Number of students answering correctly
N = Total number of students.
Example
If 110 students out of a group of total 150 students are able to solve a test item correctly,
what will be the difficulty level of that item ?
Solution
Here, N = 150
R = 110

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