Reliability Vs. Validity- Everything You Need To Know

Reliability and validity are two essential parts of any successful research. Many research scholars have come up with insightful ways to shed light on reliability vs. validity. When you write a dissertation, the quality assessment of your research is based on two factors. According to the experts, the measurement procedure must be reliable for a study to be considered as valid. Reliability refers to the degree to which research method produces stable and consistent results.

Reliability Vs. Validity

Keep reading
this blog to know more.

Reliability vs. Validity- Definition

As research
scholars define, ‘Validity is the expected outcome of a research, whereas
reliability is the consistent outcome that the research produces.’ A multi-item
measurement scale needs to be evaluated for checking the accuracy and
applicability.  Read on to understand the

What is validity and reliability in research?


The act of
validity is to remain accurate. Statistically speaking, the term validity
implies utility. It can be regarded as the most significant yardstick that
signals the degree to which research instrument gauges. There are mainly three
types of validity:

  • Content Validity: Content validity refers to the point at which the scale provides adequate coverage of the subject being tested or samples the domain of the measurement.
    It determines whether a measurement scale covers or justifies the breadth of the content  domain or the elements of the construct.
  • Criterion Validity:  Criterion validity gauges the performance of the measuring instrument. The criterion should be relevant, unbiased and reliable.
  • Construct Validity: Construct validity refers to the degree to which a test is measured. It includes:

Convergent Validity
Discriminant Validity
Nomological Validity

What is reliability in research?

If a
measurement is performed repeatedly, the consistent outcome of the research
element is the reliability. There are different ways to assess whether a
component is reliable or not. Some of the measuring components are test-retest,
internal consistency methods, and alternative forms.

There are two significant aspects of reliability:

  • Stability: The degree
    of stability can be determined by making a comparison of the results of
    repeated measurement. With a stability assessment, the element can be regarded
    as reliable.
  • Equivalence: When two
    researchers compare the observation of the same events, the equivalence in
    reliability can be gauged.

random error in the measurement process can lead to inconsistency of the
results, thus reducing the reliability. However, systematic errors do not
affect reliability. Temporary and situational factors do not interfere when
research instruments conform to reliability.

Reliable Knowledge
Valid Knowledge

How  is reliability different from validity?

Validity and Reliability

There are fundamental differences between validity and
reliability of a research. Read on to know the details.

Validity Reliability
Validity refers to a situation when a test or
instrument is accurately measuring what it’s supposed to. 
refers to the degree of reproducibility of the results if the measurement is
A valid instrument is always reliable A reliable instrument is not valid
Validity is important while evaluating the
multi-item scale.
Reliability has no role to play while evaluating a
multi-item scale.
Assessing validity is a difficult task Assessing reliability is easy  
Validity checks whether the scale produces the
expected result.
Reliability concentrates on precision, which measures
the extent to which a scale produces a consistent outcome.

Table : Difference between reliability and validity

The key differences will help you understand the definition of ‘what is reliability in research?’ Read on to know the significant roles that reliability plays in various spheres of academic research.

Role of reliability in Psychology

To understand reliability in Psychology, you need to understand how the field of Psychology works. According to experts, the field is continually evolving with an increase in the understanding of human minds. When the term reliability is associated with psychological research, it focuses on the consistency of a research study or measuring test.

Reliability vs. validity in Psychology is a complicated process. The branch of Psychology
identifies two types of reliability- internal and external. Experts are of the
opinion that both the definition can be split into internal and external

What is Internal reliability?

Internal reliability refers to the consistency of the measurement within itself. For example, a personality test should produce similar results every time.

What is External reliability?

External reliability is the extent to which a measure varies from one use
to another.

Validity in Psychology has a
different definition altogether. Internal validity can be improved by
controlling extraneous variables using standardised instructions. Whereas,
external validity can be improved by setting experiments in a more natural
environment and selecting random sampling for participants.

Role of reliability and validity in Sociological research

Before learning about the role of reliability and validity in
Sociological research, let us learn about the definition of validity in the
field of Sociology.

Validity definition in Sociology

The definition
of Validity in Sociology deals with the degree to which an instrument measures
what it intends to measure. One example of an instrument is a survey
question.  Sociology defines validity as
the process to maintain parity in the environment.

Reliability and validity examples in Sociology show how different classes of people
stay in a community and share common environment.

To put it
simply, if the number of people who receive speeding tickets in an area varies
immensely from day to day, week to week and so on, it is not a valid
measurement of predictability. If the same number of tickets is received on a
monthly or annual basis, it can be considered as reliable measurement.

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