Objective Testing of Chemistry Graduate Students in an Indian University
A. V. Khedekar University of Poona Poona 411 007, India
The use of obiective tests for the internal and external assessmenu of the students in our universities has been advocated as a plaurible examination reform. Some of the Indian ~ n i v e r s k i e shave started experimenting with the objective type of questions in combination with the conventional essay type. In countries like the United States, ohjective tests, .particularly consisting of multiple-choice questions, are used as a popular tooifor the assessment o f students a t almost all levels. As far as testing in chemistry is concerned, the testing programs by the Examinations Committee, Division of Chemical Education of the American Chemical Societv seem to have contributed considerablv to the improvement of chemical education in that country.' The construrtion of reliahle and unambieuous obiective questions needs expertise and continued hard work. I t is often feared that amatenr-constructed tests, whose items have not been pretested can he equally bad, perhaps worse, than the conventional essay type, and hence unreliable. Taking into consideration the limitations of resources, we thought i t would be worthwhile trying under Indian conditions the testing materials that are available from the ACSExaminations Committee. Such trials would indicate to what extent the materials are appropriate and effective in discriminating between good and poor students. We carried out a few such experiments in the University of Poona. Some of the interesting observations are reported here. Preparation and Administering of the Test A test consisting of 68 multiple-choice items was assembled in two parts, part I having 36 items and part 11, 32. The items were selected from a test published by the ACSExaminations C ~ m m i t t e e No . ~ changes were made in the subject matter content of the items except for making the language understandable to our students, wherever it was found desirable. The selection of the items was done in consultation with the senior university teachers who had enough experience as paper setters and examiners at the
-
Table 1.
ltem Analysis ISummaryl-Part
~efn
Ashford, T. A,, J. CHEM. EDUC., 42,496 (1965). ACS-NSTA High School Chemistry Form 1963. Fan, Chung Teh, Item Analysis Tables, Educational Testing Service, Princeton, New Jersey. Table 2.
ltem Analysis (Summaryl-Part
Refa item NO.
II
Ref
NO.
D
I
item No.
No.
D
I See footnote a- able
Ref
item NO.
NO.
P
I
item No.
No.
P
1
2
83
3
82
44 39
19 20
21
2
83 76
22
BSc. level, and therefore bad a clear idea about the scope of the BSc. syllabus in chemistry. Only those items selected unanimously were included in the test. The test was administered to a sample of 159 students, who had just passed the B.Sc. examination of the University of Poona and were admitted to the M.Sc. semester I course a t seven different centers of the University. The answer sheets collected from all the centers were subjected to detailed statistical analysis. Item analysis of the data was carried out and the D and r values were estimated by using the Item ~ n a l y s i stable^.^ The results are summarized in Tables 1and 2. For the interpretation of item analysis the norms regarding the values of difficulty level p and the discriminating index r as suggested by the ACS-Examination Committee were used. On the basis of these criteria, the items may be classified as given in Table 3. The test as a whole and also separately in parts I and I1
62 29
Table 3.
1.
Classification of Items on the Basis of p and r Valuer
Clarr
Criferion
very easy
Very difficult Pool discriminator Better amriminator Average discriminator
Table 4.
indicates the serial No. of tne item in the original test ACSNSTA High School Chemistry Form 1963 from which the item war selected. Our grateful thanks are due to Prof. T. A. Arhfard, Chairman. ACS--Examinations Committee for making the tests available to "I.
Part i
p Z 90 p40 20 < r < 40
r
1
Average Score and Standard Deviation
Maximum attainable score Mean score Standard deviation Ranse
36 18.4
5.54
3-30
32 17.25 5.52 4-30
Volume 52, Number 12 December 1975 / 803
appears to he satisfactory for discriminating between good and poor students in the sample. Generally speaking, the test may be considered of average difficulty and therefore appropriate at the level of the students sampled. The frequency distribution of the raw scores for parts I and I1 indicates a fairly normal Gaussian distribution. The average score and the standard deviation values are given in Table 4. I t may be observed that the levels a t which the test is found to he appropriate in the two countries are dif-
804 / Journal of Chemical Education
ferent. The subject content being similar a t the two levels, the same test content is appropriate in both the places. Acknowledgment
The author wishes to acknowledge with thanks the assistance from his colleagues in the University of Poona. Thanks are especially due to Prof. M. N. Palsane, Department of Experimental Psychology, for helpful suggestions and Prof. H. J. Arnikar, Head of the Department of Chemistry, for encouragement and facilities.
