Page 82 - DEDU504_EDUCATIONAL_MEASUREMENT_AND_EVALUATION_ENGLISH

Educational Measurement and Evaluation

Notes • The tests constructed for evaluating content knowledge, skill or other teaching objectives should
be established with content validity, and this is a very important task, The chief purpose of
achievement tests is to evaluate students’ knowledge and skills etc. relating to the content.
• Criterion-related Validity : When we desire to predict about future working efficiency or
performance of some individuals on the basis of some test, or we want to estimate the
performance of some individuals in a certain field, then the test has to be based on criterion-
related validity.
• According to Grounlund, “Criterion-related validity may be defined as the extent to which test
performance is related to some other valued measure of performance.”
• Construct Validity : According to Cronback and Meehl, when a test has to be analyzed in the
form of a measurer of such attributes which can be defined operationally, in such a situation,
construct validity is needed. This type of validity has been termed by Garrett as factoral.
• According to Anastasi, “The construct validity of a test is the extent to which the test may be
said to measure a theoretical construct or trait.”
• When a test appears to measure that element, trait or subject knowledge for which it has been
constructed. then it is said that it possesses face validity. In face validity, a test appears to be
valid by the form of its items.
• The chief aim of validity determination is to know whether a test is measuring that trait to the
required extent and with accuracy, so that meaningful hypotheses can be formulated on its
basis, and important decisions can be taken on its basis. Following are the important methods
of calculating validity :
(i) Simple correlation method.
(ii) Bi-serial correlation method.
(iii) Point bi-serial correlation method.
(iv) Tetrachoric correlation method.
(v) Expectancy table method.
(vi) Cut-off score method.
(vii) Differential predictors method.
(viii) Factor-analysis method.
• Simple Correlation Method : This method is the most prevalent method to calculate validity
coefficient. This is a very simple method. In this, students’ scores are compared with the
correlation efficient scores obtained on criterion.
• Bi-serial Correlation Method : Under certain situations when the individuals of a group fall
under a variable, then we can measure in the score form, but under the second variable, we
can divide into categories only those individuals, and the correlation calculated between these
two variables is called bi-serial correlation, and the variable which is divided into two categories
is called dictotomous variable.
• Point bi-serial Correlation Method : The chief difference between bi-serial correlation method
and point bi-serial correlation method is that in the point bi-serial correlation method, the
dichotomous variable is in fact discrete.
• Tetrachoric Correlation : This method is used in such a situation when both variables X and Y
are dichotomous. If they are dichotomous,rbias cannot be calculated, and in their place,
tetrachoric correlation is calculated.
• Multiple Correlation Method : This method can be used when more than one scales are used
for some hypothesis. In this, scores of different scales are used jointly in the of statistics, and
it is correlated with the third scale in order to know its multiple correlation. Multi coefficient
expresses correlation between one distribution of scores and two or more co-distributions.

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