It will be helpful to undergraduate and post graduate students of Education and Psychology

1. Validity: Meaning, Methods and Factors
Affecting Validity of Test
Dr. Sarat Kumar Rout
Assist. Prof. Department of Education
Ravenshaw University, Cuttack
Email:saratrout2007@rediffmail.com

2. What is Validity?
• Validity is the extent to which a test measures what it
claims to measure. It is vital for a test to be valid in
order for the results to be accurately applied and
interpreted.
http://psychology.about.com/od/researchmethods/f/validity.htm
• The extent to which a test adequately represents the
subject matter content or behavior to be measured
commonly used in evaluating achievement or proficiency
tests.
http://www.education.com/definition/content-validity

3. Content Validity
• If an assessment encompasses wide range or large proportion of
syllabus or content from a book or area that will fall in the domain of
content validity.
• When a test has content validity, the items on the test represent
the entire range of possible items the test should cover.
Individual test questions may be drawn from a large pool of items
that cover a broad range of topics.
http://psychology.about.com/od/researchmethods/f/validity.htm
•Content Validity is called appropriateness of the test; that is
appropriateness of the sample and the learning level.
•Content Validity is the most important type of validity which can be
achieved through a careful examination of the test content.
•It provides the most useful subjective information about the
appropriateness of the test.

4. Contd.
• Content validity • Example – Social Science Exam; –
Assume it contains all aspects of the Social Science
(History, Political Science, Economics, Geography etc.,)
• If a person scores high on this test, we can ‘infer’ that he
knows much about the subject (i.e., our inferences about
the person will right across various situations).
• In contrast, if the exam did not contain anything about
Political Science, the inferences we make about a high
scorer may be wrong most of the time and vice versa.

5. Contd.
• Generally, a measures/scores that includes a more
representative sample of the target behaviour will have more
content validity and hence lead to more accurate inferences.
• Reliability places an upper limit on validity (the maximum
validity is the square root of reliability coefficient.) the higher
the reliability the higher the maximum possible validity.
Example rtt=.79, validity index will be maximum=.88
• One exception is that between internal consistency and
validity (better to sacrifice IC to content validity) – The
ultimate aim of test is inferential which depends more on
content validity than internal consistency.

6. Formula for distribution marks
• Formula for allocation of marks to different units of a subject:
= Total No. Pages in Unit/Total No. Pages of the books X
100
• Formula for allocation of marks to subjective/objective type questions
= (% weightage to subjective/objective type questions)⁄100
X Total No. of Marks Per Unit

7. Steps for content validation
• Step-I: Formulation of objectives
• Step-II: Specification of content, types of questions
• Step-III: Preparation of the test items
• Step-IV: Expert validation/Statistical verification

8. Marks allocation-Example
Using content validity sheet a teacher can save the time
and energy while developing exam papers.
S. No. Chapter/Unit No. of
Pages
Allocated
Marks
Subjective
(60 %)
Objective
(40 %) %
Total
Marks (%)
01 Rise of
Nationalism in
India
23 23/125X100=18
(18 % or 18
marks out of
100)
60/100X
18 =11
40/100 X
18 =7
18

9. 2. Criterion Validity
• Criterion-related validity investigates the extent of
correspondence/agreement between the scores
obtained from the newly-developed test and the
scores obtained on an independent outside criterion
available at present or available in the future.
• Two types
1. Concurrent validity
2. Predictive validity

10. Contd.
1. Concurrent validity
In order to find out concurrent validity both the newly-
developed test and independent outside criterion
measure will be administered to the same group at the
same time. The extent of agreement/correspondence will
be calculated by applying product moment coefficient
correlation or discrimination.
Example: scores obtained on a newly constructed
achievement test on English Language of Class-X may
be correlated with scores obtained on an already
standardized achievement test on English Language.
The resulting coefficient of correlation will be an indicator
of concurrent validity.

11. Contd.
Steps for concurrent validation
• Step-I:The newly constructed test will be administered to
a defined group of individuals/learner.
• Step-II: The independent outside criterion measure/test
will be administered to the same group at the same time.
• Step-III: The two sets of scores are correlated.
• Step-IV: The resulting coefficient indicates the
concurrent validity.
• Concurrent validation is most suitable to tests meant for
diagnosis of the present status rather than for
prediction of future outcomes.

12. Contd.
2. Predictive validity
In order to find out predictive validity of a newly
constructed test, the test constructer will administered it
on a defined group of individuals/learners and then a
time gap of months or year will be allowed and
subsequently, independent outside criterion
measures/scores will be obtained by administering a
test to the same group. The extent of
agreement/correspondence between two sets of
measures/scores will be calculated by applying product
moment coefficient correlation or discrimination.
Example: Predictive validity of entrance test for college
admission to assess if a person will graduate or not.

13. Contd.
Steps for concurrent validation
• Step-I:The newly constructed test will be administered to
a defined group of individuals/learner.
• Step-II: The independent outside criterion
measure/scores will be obtained from the same group
after a gap (month/year).
• Step-III: The two sets of scores are correlated
• Step-IV: The resulting coefficient indicates the predictive
validity.
• Predictive validity is needed for tests meant for long
range forecast of academic achievement, vocational
success.

14. Contd.
• A comparative study of predictive validity and the
concurrent validity has revealed that for the same test
predictive validity is usually lower than the
concurrent validity . The degree of agreement between
the test and criterion decrease over time.
Example: The relationship between Academic aptitude
test and the present achievement of learners.
• Test constructer face problem in selection of
appropriate and adequate criterion which is more
acute in predictive validity than the concurrent
validity of a test.

15. Construct Validity
• Construct validation is a more complex and difficult
process than the content and criterion validation.
• Hence the investigator decides to compute construct
validity only when he is fully satisfied that neither any
valid and reliable criterion is available to him.
• Other names of the construct validity factorial validity or
trait validity.
• “The extent which the test may be said to measure a
theoretical construct”.
• What is a construct? A construct is non observable trait
(anxiety, pain, intelligence).

16. Contd.
Steps for validation of the construct
Step-I: Specifying the possible different measures of the
construct.
Step-II: Determining the extent of correlation between all or
some of those measures of the construct.
Step-III: Determining whether or not al or some measures act as
if they were measuring the construct.

17. Steps for validation of the construct
Step-I: Specifying the possible different measures of the
construct.
Example: Intelligence as a ‘Construct’
Possible different measures of Intelligence are
1. Quick decision taking ability
2. Ability to operate with symbols
3. Ability to learn
4. Capacity to modify behavior
5. Verbal fluency
6. Ability to comprehend verbal material .
7. Original and critical thinking etc.

18. Contd.
Step-II: Determining the extent of correlation between all
or some of those measures of the construct.
• Empirical investigation to find out correlation to find out
the extent to which various measures are correlated with
each other.
Some measures may correlate with each other and
form cluster. As 1, 4 and 5 may be a cluster and 2, 6
and 7 like wise.
All measures of a construct may highly correlate with
each other.
All measure may correlate with each other poorly.

19. Contd.
Step-III: Determining whether or not all or some
measures act as if they were measuring the construct.
– Now to determine whether or not such measures
behave with reference to other variables of interest in
an expected manner.
– For example, highly correlating measures from
among the above seven supposed measures for
intelligence should show at least some moderated
correlation with teachers ratings, grades in class and
examination marks.

20. Contd.
• Content and criterion can be established in one or two
studies, but there is no single experiment that can prove
a construct.
• Construct validation is an ongoing process, learning
more about the construct, making new predictions and
then testing them.
• Each supportive study strengthens the construct but one
well designed negative study can question the entire
construct.

21. Factors affecting Validity
1. Length of the Test: (Homogeneous Vs Heterogeneous)
Formula for estimating validity by lengthening the test as
rc(nx)=(n) (rcx)/√n+n(n-1)rtt
rc(nx)=correlation between criterion and the test length ‘n’ times.
n=number of times test has been lengthened.
rcx= correlation between criterion and the test in original length.
rtt=reliability coefficient of the test.
2. Range of ability
3. Ambiguous directions
4. Socio-cultural differences
5. Addition of inappropriate items

22. Relationship of validity to reliability
• Validity is the correlation of the test with some outside
independent criteria and reliability of the test is the self-
correlation of the test
• A test which is not correlating with itself is not expected
to correlate with out side independent criteria. Thus
validity depends on reliability.-For homogeneous test.

23. Contd.
• In heterogeneous test validity may be higher than the
reliability. Thus reliability is necessary but not sufficient
condition for validity-Example Achievement test in Social
science having different sections of question from
History, pol. Science, geography and economics.
• Theoretically, maximum validity coefficient between two
variables is equal to the square root of the product of
their reliabilities.
• A test constructor should not always aim at high
reliability and high validity from the same test.

24. Thank you one and all