This document discusses criteria for good measurement in research. It identifies three key criteria: validity, reliability, and sensitivity. Validity refers to a measure accurately reflecting what it intends to measure. There are four types of validity: face validity, content validity, criterion-related validity (which has concurrent and predictive validity), and construct validity (which has convergent and discriminant validity). Reliability indicates a measure is free of bias and consistently measures a concept over time. Two aspects of reliability are stability (via test-retest and parallel-form reliability) and internal consistency. Sensitivity refers to how well a measure distinguishes between variables it is intended to measure.

1. Criteria for Good Measurement
Sushant Kumar Sinha
Sushovan Bej

2. Criteria for good measurements?
“The use of better instrument will ensure more
accuracy in results, which in turn, will enhance the
scientific quality of the research”
There are three measurement of the characteristics for
evaluating a measurement tool.
1. Validity
2. Reliability
3. Sensitivity

3. Validity
It is the ability of an instrument to measure what it is
supposed to measure.
That is, when we ask a questions with the hope that we
are tapping the concept, how can we be reasonably
certain that we are indeed measuring the concept we
set out to do and not something else?

4. Establishing Validity
Researcher have attempted to assess validity in many ways.
They attempt to provide some evidence of a measure’s
degree of validity by answering a variety of questions
There are four basic approaches to establishing validity are
widely classified as following
1. Face Validity
2. Content Validity
3. Criterion-Related Validity
4. Construct Validity

5. Face Validity
It is considered as a basic and very minimum index of content validity.
It indicates that the items that are intended to measure a concept, do
on the face of it look like they measure the concept.
For e.g. a few people would accept a measure of college student math
ability using a question that asked students: 2 + 2 = ? This is not a valid
measure of collegelevel math ability on the face of it.
Nevertheless, it is a subjective agreement among professionals that a
scale logically appears to reflect accurately what it is supposed to
measure. When it appears evident to experts that the measure provides
adequate coverage of the concept, a measure has face validity

6. Continued…
Clear, understandable questions such as “How many children do you
have?” generally are agreed to have face validity. But it becomes more
difficult to assess face validity in regard to more complicated
business phenomena.
For instance, consider the concept of customer loyalty. Does the
statement “I prefer to purchase my groceries at Delavan Fine Foods”
appear to capture loyalty? How about “I am very satisfied with my
purchases from Delavan Fine Foods”? What about “Delavan Fine
Foods offers very good value”? While the first statement appears to
capture loyalty, it can be argued the second question is not loyalty
but rather satisfaction. What does the third statement reflect? Do we
think it looks like a loyalty statement?

7. Content Validity
The content validity of a measuring instrument is the
extent to which it provides adequate coverage of the
investigate questions guiding the study. If the
instrument contains a representative sample of the
universe of subject matter of the interest, then the
content validity is good.
To put it differently, content validity is a function of
how well the dimensions and elements of a concept
have been delineated

8. Continued…
Look at the concept of feminism which implies a person's
commitment to a set of beliefs creating full equality between men and
women in areas of the arts, intellectual pursuits, family, work, politics,
and authority relations. Does this definition provide adequate coverage
of the different dimensions of the concept?
Then we have the following two questions to measure feminism:
1. Should men and women get equal pay for equal work?
2. Should men and women share household tasks?
These two questions do not provide coverage to all the dimensions
delineated earlier. It definitely falls short of adequate content validity
for measuring feminism

9. CriterionRelated Validity
Criterion validity uses some standard or criterion to
indicate the a construct accurately. The validity of an
indicator is verified by comparing it with another
measure of the same construct in which research has
confidence.
There are two subtypes of this kind of validity
1. Concurrent Validity
2. Predictive Validity

10. Concurrent Validity
To have concurrent validity, an indicator must be associated with
a preexisting indicator that is judged to be valid.
For e.g. we create a new test to measure intelligence. For it to be
concurrently valid, it should be highly associated with existing
IQ tests (assuming the same definition of intelligence is used). It
means that most people who score high on the old measure
should also score high on the new one, and vice versa.
The two measures may not be perfectly associated, but if they
measure the same or a similar construct, it is logical for them to
yield similar results.

11. Predictive Validity
Criterion validity whereby an indicator predicts future events that are
logically related to a construct is called a predictive validity. It cannot be
used for all measures. The measure and the action predicted must be
distinct from but indicate the same construct. Predictive measurement
validity should not be confused with prediction in hypothesis testing,
where one variable predicts a different variable in future.
For e.g. looking at the scholastic assessment tests being given to candidates
seeking admission in different subjects. These are supposed to measure the
scholastic aptitude of the candidates the ability to perform in institution as
well as in the subject. If this test has high predictive validity, then
candidates who get high test score will subsequently do well in their
subjects. If students with high scores perform the same as students with
average or low score, then the test has low predictive validity

12. Construct Validity
Construct validity is for measures with multiple indicators.
It addresses the question: If the measure is valid, do the
various indicators operate in consistent manner? It
requires a definition with clearly specified conceptual
boundaries. In order to evaluate construct validity, we
consider both theory and the measuring instrument being
used.
There are two subtypes of this kind of validity
1. Convergent Validity
2. Discriminant Validity

13. Convergent Validity
Convergent validity means that multiple measures of the
same construct hang together or operate in similar ways.
For e.g. we construct "education" by asking people how
much education they have completed, looking at their
institutional records, and asking people to complete a test
of school level knowledge. If the measures do not converge
(i.e. people who claim to have college degree but have no
record of attending college, or those with college degree
perform no better than high school dropouts on the test),
then our test has weak convergent validity and we should
not combine all three indicators into one measure.

14. Discriminant Validity
Also called Divergent validity, discriminant validity is the
opposite of convergent validity. It means that the indicators of
one construct hang together or converge, but also diverge or are
negatively associated with opposing constructs. It says that if two
constructs A and B are very different, then measures of A and B
should not be associated.
For example, we have 10 items that measure political
conservatism. People answer all 10 in similar ways. But we have
also put 5 questions in the same questionnaire that measure
political liberalism. Our measure of conservatism has
discriminant validity if the 10 conservatism items hang together
and are negatively associated with 5 liberalism ones.

15. Reliability
The reliability of a measure indicates the extent to
which it is without bias (error free) and hence ensures
consistent measurement across time and across the
various items in the instrument.
In other words, the reliability of a measure is an
indication of the stability and consistency with
which the instrument measures the concept and helps
to assess the “goodness” of measure

16. Stability
The ability of the measure to remain the same over
time despite uncontrollable testing conditions or the
state of the respondents themselves is indicative of its
stability and low vulnerability to changes in the
situation.
This attests to its "goodness" because the concept is
stably measured, no matter when it is done.
Two tests of stability are testretest reliability and
parallelform reliability

17. Test-Retest Reliability
Testretest method of determining reliability involves administering the same
scale to the same respondents at two separate times to test for stability. If the
measure is stable over time, the test, administered under the same conditions
each time, should obtain similar results.
For example, suppose a researcher measures job satisfaction and finds that 64
percent of the population is satisfied with their jobs. If the study is repeated a
few weeks later under similar conditions, and the researcher again finds that 64
percent of the population is satisfied with their jobs, it appears that the
measure has repeatability.
The high stability correlation or consistency between the two measures at
time 1 and at time 2 indicates high degree of reliability. This was at the
aggregate level; the same exercise can be applied at the individual level. When
the measuring instrument produces unpredictable results from one testing to
the next, the results are said to be unreliable because of error in measurement.

18. ParallelForm Reliability
When responses on two comparable sets of measures
tapping the same construct are highly correlated, we have
parallelform reliability. It is also called equivalentform
reliability.
Both forms have similar items and same response format,
the only changes being the wording and the order or
sequence of the questions. What we try to establish here is
the error variability resulting from wording and ordering of
the questions. If two such comparable forms are highly
correlated, we may be fairly certain that the measures are
reasonably reliable, with minimal error variance caused by
wording, ordering, or other factors.

19. Internal Consistency of Measure
Internal consistency of measures is indicative of the
homogeneity of the items in the measure that tap the
construct.
In other words, the items should `hang together as a set'
and be capable of independently measuring the same
concept so that the respondents attach the same overall
meaning to each of the items. This can be seen by
examining if the items and the subsets of items in the
measuring instrument are highly correlated. Consistency
can be examined through the interitem consistency
reliability and splithalf reliability.

20. Inter-item Consistency reliability
This is a test of consistency of respondent’s
answers to all the items in a measure. To the degree
that items are independent measures of the same
concept, they will be correlated with one another

21. Split-Half Reliability
It reflects the correlation between two halves of an
instrument. The estimates could vary depending on how
the items in the measure are split into two halves.
The technique of splitting halves in the most basic method
for checking internal consistency when measures contain a
large number of items. In the split-half method the
researcher may take the results obtained from one half of
the scale items(e.g. odd-numbered items) and check them
against the results from the other half of the items (e.g.
even numbered items). The high correlation tells us there
is similarity (or homogeneity) among its items.

22. Reliability vs Validity
Reliability is a necessary but not sufficient condition
for validity. A reliable scale may not be valid.
For example, a purchase intention measurement
technique may consistently indicate that 20 percent of
those sampled are willing to purchase a new product.
Whether the measure is valid depends on whether 20
percent of the population indeed purchases the
product. A reliable but invalid instrument will yield
consistently inaccurate results