Validity by Dr.Shazia Zamir

1. VALIDITY
BY
DR.SHAZIA ZAMIR

2. VALIDITY
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Validity Refers to the degree which the tool
measures, what it is intended to measure,
It refers to whether the instrument or scale is
quantifying what it claims to.
Does it measure what you think it measures.
e.g. ‘Weight’ scale measures body weight and it is
valid.

3. VALIDITY
• VALIDITY TELLS YOU HOW ACCURATELY A METHOD MEASURES SOMETHING. IF A
METHOD MEASURES WHAT IT CLAIMS TO MEASURE, AND THE RESULTS CLOSELY
CORRESPOND TO REAL-WORLD VALUES, THEN IT CAN BE CONSIDERED VALID.
• CONSTRUCT VALIDITY: DOES THE TEST MEASURE THE CONCEPT THAT IT’S
INTENDED TO MEASURE?
• CONTENT VALIDITY: IS THE TEST FULLY REPRESENTATIVE OF WHAT IT AIMS TO
MEASURE?
• CRITERION VALIDITY: DO THE RESULTS CORRESPOND TO A DIFFERENT TEST OF THE
SAME THING?

4. WHAT IS A CONSTRUCT?
• A construct refers to a concept or characteristic that can’t be directly
observed, but can be measured by observing other indicators that are
associated with it.
• Constructs can be characteristics of individuals, such as intelligence,
obesity, job satisfaction, or depression; they can also be broader concepts
applied to organizations or social groups, such as gender equality or
freedom of speech.
• Example: There is no objective, observable entity called “depression” that
we can measure directly. But based on existing psychological research and
theory, we can measure depression based on a collection of symptoms and
indicators, such as low self-confidence and low energy levels.

5. WHAT IS CONSTRUCT VALIDITY?
• Construct validity is about ensuring that the method of measurement
matches the construct you want to measure. If you develop a
questionnaire to diagnose depression, you need to know: does the
questionnaire really measure the construct of depression? Or is it actually
measuring the respondent’s mood, self-esteem, or some other construct?
• To achieve construct validity, you have to ensure that your indicators and
measurements are carefully developed based on relevant existing
knowledge. The questionnaire must include only relevant questions that
measure known indicators of depression.
• The other types of validity described below can all be considered as forms
of evidence for construct validity.

6. CONTENT VALIDITY
• Content validity assesses whether a test is representative of all aspects
of the construct.
• To produce valid results, the content of a test, survey or measurement
method must cover all relevant parts of the subject it aims to measure. If
some aspects are missing from the measurement (or if irrelevant aspects
are included), the validity is threatened.
• Example: A mathematics teacher develops an end-of-semester algebra
test for her class. The test should cover every form of algebra that was
taught in the class. If some types of algebra are left out, then the results
may not be an accurate indication of students’ understanding of the
subject. Similarly, if she includes questions that are not related to
algebra, the results are no longer a valid measure of algebra knowledge.

7. FACTORS AFFECTING VALIDITY
Some factors that may affect the test validity are discussed as under as mentioned below:-
Instructions to Take A Test:
The instructions with the test should be clear and understandable and it should be in simple
language. Unclear instructions may restrict the pupil how to respond to the items, whether it
is permissible to guess, and how to record the answers will tend to reduce validity.
Difficult Language Structure:
Language of the test or instructions to the test that is too complicated for the pupils taking
the test will result in the test’s measuring reading comprehension and aspects of
intelligence, which will distort the meaning of the test results. Therefore it should be simple
considering the grade for which the test is meant.
Inappropriate Level of Difficulty:
In norm-references tests, items that are too easy or too difficult will not provide reliable
discriminations among pupils and will therefore lower validity. In criterion-referenced tests,
the failure to match the difficulty specified by the learning outcome will lower validity.

8. FACTORS AFFECTING VALIDITY
4.Poorly constructed test items:
There may be some items that provide direction to the answer or test items
that unintentionally provide alertness in detecting clues are poor items, these
items may harm the validity of the test.
5.Ambiguity in items statements:
Ambiguous statements in test items contribute to misinterpretations and
confusion. Ambiguity sometimes confuses the better pupils more than it does
the poor pupils, causing the items to discriminate in a negative direction.
6.Length of the test:
A test is only a sample of the many questions that might be asked. If a test is
too short to provide a representative sample of the performance we are
interested in, its validity will suffer accordingly. Similarly a too lengthy test is