A Presentation on educational assessment and evaluation

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Educational Measurement and
Evaluation
Course Code : 6507

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Qualities of Good Test
UNIT: 2
Prepared By
Gulnaz Akbar

4. Objectives
 After this presentation students will be able to:
 Define validity and reliability of the test
 Explain the nature of reliability
 Differentiate between validity and reliability
 Identify various techniques of estimating reliability
 Specify the significance of validity
 Enlist basic considerations effecting reliability and
validity

5. Reliability
 Reliability is the degree of consistency of a measure.
 A test will be reliable when it gives the same repeated
result under the same conditions.
 Reliability can be determined statistically by
calculating the correlation coefficient.
 If a test is reliable it should show a high positive
correlation between repeat scores.

6. Methods of Estimating Reliability
 Test Retest
 Equivalent Forms method
 Split Half Method
 Kudar Richardson Method

7. Test Retest Method
 To estimate reliability by means of the test-retest
method, the same test is administered twice to the
same group of pupils with a given time interval
between the two administrations of the test.
 In this method the time interval plays an important
role.

8. Equivalent Forms method
 Estimating reliability by means of the equivalent form
method involves the use of two different but
equivalent forms of the test.
 Parallel form reliability is also known as Alternative
form reliability or Equivalent form reliability or
Comparable form reliability.
 In this method two parallel or equivalent forms of a
test are used.

9. Split Half Method
 Split-half method is an improvement over the earlier
two methods, and it involves both the characteristics
of stability and equivalence.
 In this method the test is administered once on the
sample and it is the most appropriate method for
homogeneous tests.
 To estimate reliability, Spearman-Brown Prophecy
formula is used.

10. Standard Error of Measurement
 The standard error of measurement (SEm) estimates
how repeated measures of a person on the same
instrument tend to be distributed around his or her “true”
score.
 The true score is always an unknown because
no measure can be constructed that provides a perfect
reflection of the true score.
 It is closely associated with the error variance, which
indicates the amount of variability in a test administered to
a group that is caused by measurement error.

11. Factors Affecting Reliability
 Length of test
 Range of talent
 Spread of Scores
 Testing conditions
 Difficulty of Test

12. Validity
 Validity is the extent to which a concept, conclusion
or measurement is well-founded and likely
corresponds accurately to the real world.
 A test measures what it is intended to measure

13. Types of Validity
 Content Validity
 Concurrent Validity
 Predictive Validity
 Construct Validity

14. Content Validity
 In content validity, you essentially check the
operationalization against the relevant content
domain for the construct.
 This approach assumes that you have a good detailed
description of the content domain, something that’s
not always true

15. Concurrent Validity
 In concurrent validity, we assess the
operationalization’s ability to distinguish between
groups that it should theoretically be able to
distinguish between.

16. Predictive Validity
 In predictive validity, we assess the
operationalization’s ability to predict something it
should theoretically be able to predict.

17. Construct Validity
 Construct validity evaluates whether a measurement
tool really represents the thing we are interested in
measuring.
 It’s central to establishing the overall validity of a
method.

18. Factors Influencing Validity
 Numerous factors influencing validity of an
instrument.
 Factors in the test itself influencing validity:
Unclear Directions
Reading vocabulary and sentence structure too difficult
Inappropriate level of difficulty
Poorly constructed test items
Improper arrangement of items

19. Factors in Test Administration and
Scoring
 The administration and scoring of test may also
introduce factors that have a effect on validity.
 For all types of test psychological and physical
conditions at the time of testing may also have a
negative effect.

20. Objectivity and Usability
 Usability and Practicality
 Ease of Administration
 Time Required for Administration
 Ease of Scoring
 Ease of Interpretation and Application
 Availability of Equivalent or Comparable Forms
 Cost of Testing

21. Self Assessment Questions
 What is reliability?
 What is validity?
 Describe methods of estimating reliability
 Descibe different types of validity

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Any Question ???

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Thank You