Validity

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validity

Definition

“Test should be measure what is supposing to measure.”

Validity is the best available approximation to the truth of a given proposition, inference, or conclusion.

Test Validity

Definition

Validity is the degree to which the test actually measures what its purports to measure is called test validity.”

Introduction:

Validity is the most important issue in psychological and educational testing because it concerns the meaning placed on test result through many text books present validity as a static construct, various models of validity involved since the first published recommendation for constructing psychological and educational tests. These models can be categorized into two primary groups.

Classical Models – which include several types of validity.

Modern Models – which present validity as a single construct.

The modern model recognized classical “validities” into either “aspects” of validities or types of validity supporting evidence.

VALIDITY: Synonyms and Related Words. What is Another Word for VALIDITY? -  GrammarTOP.com

Historical Background

Although psychologists and educators were aware of several facts of validity before second world war their methods for establishing validity were commonly restricted to correlation of test scores with some known criterion under the direction of Lee Cronach. The 1954 technical recommendations for psychological test and diagnostic techniques attempted of clarity and broaden the scopes of validity by dividing it into the parts.

  1. Content Validity
  2. Criterion Validity
    1. Predictive Validity
    2. Concurrent Validity

Content Validity

Over the next decades, many theorists, including Cranach himself, voiced their dissatisfaction’s with this three-in-one models of validity. Their arguments culminated in “Samuel Messick” 1995 article that described validity as a single construct composed of six aspects. In his view various infe rences made from test scores may require different types of evidence, but not different validities.

Types of Validity:

  1. Content of Validity
  2. Criterion Validity
  3. Construct Validity

1.        Content Validity

Content validity occurs when the experiment provides adequate coverage of the subject being studied. This includes measuring the right things as well as having an adequate sample. Samples should be both large enough and be taken for appropriate target groups.

Validity

Content validity refers to the ability of a test to sample adequately the board range of elements that compose a particular construct.

2.        Criterion Validity

This examines the ability of the measure to predict a variable that is designated as criterion. A criterion may well be an extremely defined “good standard”. Achieving this level of validity, this makes results more credible.

Example:

Before actually using a test to predict whether someone will be at a particular job, you would first want to determine whether persons are already doing well at job (the criterion measure) also tend to score high on your proposed test. It so, then you know the test scores are related to the criterion.

It has further two types:

    1. Predictive Validity
    2. Concurrent Validity

Predictive Validity:

It measures the extent to which a future level of variable can be predicted from a current measurement. This includes correlation with measurement made with different instrument.

College entry test should have a high predictive validity with regard to final exam result.

Concurrent Validity:

It measures the relationship between measures made with existing test. The existing test is the criterion.

Example: A measure of creativity should correlate with existing measure of creativity.

3.        Constructive Validity

Construct validity occurs when the theoretical construct of cause and effect accurately represent the real world situations they are intended to model. This is relating to how well the experiment is operationalized.

A good experiment turns the theory constructs into actual things you can measure. Sometimes just finding out more about the construct which itself must be valid can be helpful.

Construct validity is thus as assessment of the quality of an instrument of experimental design.

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