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Educational Measurement and Evaluation Kulwinder Pal, Lovely Professional University

Notes Unit 7 : Reliability – Types , Methods and Usability

CONTENTS
Objectives
Introduction
7.1 Reliability
7.2 Types of Reliability
7.3 Methods of Reliability
7.4 Usability of Reliability
7.5 Summary
7.6 Keywords
7.7 Review Questions
7.8 Further Readings

Objectives

The objectives of this unit can be summarised as below :
• To discuss about the reliability
• To describe about the types of reliability
• To explain about the methods of reliability
• To discuss about the usability of reliability

Introduction

Reliability is one of the most important elements of test quality. It has to do with the consistency,
or reproducibility, of an examinee’s performance on the test. For example, if you were to
administer a test with high reliability to an examinee on two occasions, you would be very
likely to reach the same conclusions about the examinee’s performance both times. A test with
poor reliability, on the other hand, might result in very different scores for the examinee across
the two test administrations. If a test yields inconsistent scores, it may be unethical to take any
substantive actions on the basis of the test. There are several methods for computing test reliability
including test-retest reliability, parallel forms reliability, decision consistency, internal consistency,
and interrater reliability. For many criterion-referenced tests decision consistency is often an
appropriate choice.

7.1 Reliability

7.1.1 Meaning of Reliability

By reliability is mean to rely or trust. Generally we trust many things in our daily life without
giving much thought to them. This trust is not formed over one or two days, but a strong
assumption is created after having perceived those objects over a long period of time. This is the
reason that a shopkeeper or friend becomes reliable and his opinion is accepted without any
debate or argument.

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