Validity, Its Types,
Measurement & Factors
For Psychology Students.
“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
•TYPES OF VALIDITY
There are the following types of validity;
It is the extent to which the
measurement method appears “on its
face” to measure the construct of interest.
People might have negative reactions to
an intelligence test that did not appear
to them to be measuring their
It is the extent to which the measurement
method covers the entire range of
relevant behaviors, thoughts, and
feelings that define the construct being
One’s attitude toward an object is considered to consist of thoughts
about the object, feelings about the object, and behaviors toward the
Therefore, a test to assess one’s attitude toward taxes should
include items about thoughts, feelings, and behaviors.
If test anxiety is thought to include both nervous feelings and
negative thoughts, then any measure of test anxiety should cover
both of these aspects.
A course exam has good content validity if it covers all the material
that students are supposed to learn and poor content validity if it
• Criterion Validity:
It is the extent to which people’s scores
are correlated with other variables
or criteria that reflect the same construct.
An IQ test should correlate positively with
An occupational aptitude test should
correlate positively with work performance.
•TYPES OF CRITERION VALIDITY:
A new measure of self-esteem should
correlate positively with an old
When the criterion is something that will
happen or be assessed in the future, this
is called predictive validity.
When the criterion is something that is
happening or being assessed at the
same time as the construct of interest, it
is called concurrent validity.
• Discriminant Validity:
It is the extent to which people’s scores are not correlated with other
variables that reflect distinct constructs.
Imagine, that a researcher with a new measure of self-esteem
claims that self-esteem is independent of mood; a person with high
self-esteem can be in either a good mood or a bad mood (and a
person with low self-esteem can too).
Then this researcher should be able to show that his self-esteem
measure is not correlated (or only weakly correlated) with a valid
measure of mood.
If these two measures were highly correlated, then we would
wonder whether his new measure really reflected self-esteem as
opposed to mood.
It is the extent to which the results of a research
study can be generalized to different situations,
different groups of people, different settings,
different conditions, etc.
It is basically the extent to which a study is free
from flaws and that any differences in a
measurement are due to an independent
variable and nothing else.
It refers to the extent to which the findings
can be generalized to other populations of
It refers to the extent to which the findings
can be generalized beyond the present
•Measurement of Validity:
There are some extremely important points to remember about the
way that psychologists evaluate the validity of a measurement
1. First, this process requires empirical evidence. A measurement
method cannot be declared valid or invalid before it has ever been
used and the resulting scores have been thoroughly analyzed.
2. Second, it is an ongoing process. The conclusion that a measurement
method is valid generally depends on the results of many studies
done over a period of years.
3. Third, validity is not an all-or-none property of a measurement
method. It is possible for a measurement method to judged
"somewhat valid" or for one measure to be considered "more valid"
It would be fine to conclude that an
English-language achievement test is
valid for children who are native English
speakers but not for children who are still
in the process of learning English.
Factors Affecting Validity :-
1. History:- events that occur besides the treatment (events in the environment).
2. Maturation:- physical or psychological changes in the participants.
3. Testing:-effect of experience with the pretest - - become testwise.
4. Instrumentation:- learning gain might be observed from pre to posttest simply due to
nature of the instrument. Particularly a problem in observation studies when observers
more likely to give ratings based on expectations (conscious or subconscious).
5. Statistical Regression:-Tendency for participants whose scores fall at either extreme
on a variable to score nearer the mean when measured a second time.
6. Differential Selection:-Effect of treatment confounded with other factors because of
differential selection of participants, problem in non random samples.
7. Experimental Mortality:-participants lost from the study, attrition.
8. Selection-maturation Interaction:- similar to differential selection, except maturation is
the confounding variable.
9. Experimental Treatment Diffusion:-Treatment is perceived as highly desirable and
members of control group seek access.
10. Compensatory Rivalry by Control Group:- (John Henry Effect) - - control group
performs beyond expectations because they perceive they are in competition with
11. Compensatory Equalization of Treatments:- occurs when experimental group
received goods or services perceived as desirable and control group is given similar goods
and services on compensate. Not comparing treatment with no treatment but one
treatment with another.
12. Resentful Demoralization of Control Group:- Control group becomes discouraged
because they perceive experimental group is receiving a desirable treatment that is being
withheld from them.