CONSTRUCT VALIDITYConstruct Validity is the extent to which a test measures a theoretical construct.

Two Points to RememberA test user implicitly accepts the definition of the construct used by those who developed and validated the test.When you use a test for a construct such as Creativity, you are not measuring creativity as such but behaviors the test developer decided would count as indicators of creativity.

An Example of Construct DevelopmentSelf EfficacyThis abstract construct was proposed by Albert Bandura (1977):Expectations of personal efficacy determine whether coping behavior will be initiated, how much effort will be expended, and how long it will be sustained in the face of obstacles and aversive experiences (p. 191).

Sources of Self-EfficacyPerformance AccomplishmentsVicarious Experience: Watching othersVerbal Persuasion: Messages received from othersEmotional Arousal: Anxiety or attention

Construct ExplicationThere are three steps for defining or explaining a psychological construct:Identify the behaviors that relate to the construct.Identify other constructs that may be related to the construct being explained.Identify behaviors related to similar constructs.

A Nomological NetworkA Nomological (law-like) network involves illustrating a constructs relation to as many other constructs and behaviors as possible.The nomological network provides the basis for a number of hypotheses about the behaviors that people who have people who have more or less quantities of a construct should display.

An example of a nomological network for intelligenceWe would expect that tested intelligence would be related to:Academic Achievement as measured by GPATests designed to measure creativity.

A Nomological Network for Self-EfficacyWe would expect people with high self efficacy to: express positive attitudes regarding their own competenceDisplay persistence in accomplishing a new and difficult task

Establishing evidence of construct validity is the process of testing the predictions made by the nomological network

Summary Points1. Construct Explication is the basis for establishing a tests construct validity. -A construct must be part of a theory that defines the construct in observable and measurable term.2. A nomological network: defines a construct by illustrating its relation to other constructs and behaviors

Gathering Evidence of Construct ValidityGathering theoretical evidence:Establishing a nomological networkPropose experimental hypotheses. Gathering Psychometric Evidence

Gathering Psychometric Evidence

Gathering Psychometric Evidence:ReliabilityConvergent ValidityDiscriminant ValidityExperimental InterventionsContent ValidityCriterion-Related validity

ReliabilityTo show a test measures a single theoretical construct there should be evidence of internal consistency (or homogeneity).Test-retest reliability is also important, to ensure that the theoretical predictions hold true over time.

Convergent ValidityConvergent Validity is a strong correlation between the test and other tests measuring the same or similar constructsExample: We would expect that two measures of general self-efficacy to yield strong, positive, and statistically significant correlations. They might also correlate with scores of task specific tests, such as mathematical or managerial self efficacy.

Related ConstructsConvergent validity is also established when there are positive correlations with measures of constructs that the underlying theory says are related.Example Self-efficacy theory suggests that self-efficacy is related to competency.

Discriminant ValidityWhen the test scores are not correlated with unrelated constructs, there is evidence of discriminant validity.Example: There would probably be an insignificant correlation between self-efficacy and artistic aptitude

Multitrait-Multimethod MethodIn 1959, Campbell and Fisk cleverly combined the need to collect evidence of reliability, convergent validity, and discriminant validity in one study.

The Logic of Multitrait-Multimethod DesignThis design allows investigators to test for:convergence across different measuresof the same thingand for divergence between measuresof related but conceptually distinct things (Cook & Campbell, 1979, p 61).

Implementing Multitrait-Multimethod MeasuresThe researcher chooses three constructs that are unrelated in theory and three types of testssuch as objective, projective, and a peer ratingto measure each of the constructs.In this way, data are collected on each participant in the study on each construct using each method.

Interpreting Multitrait-Multimethod MatrixOne would look forand expect to find high reliability estimates for each measure, high validity coefficients for tests with different formats measuring the same construct, and low correlation coefficients for tests with different formats measuring different constructs.