the nomological network. what is the nomological net? l an idea developed by cronbach, l. and meehl,...

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The Nomological Network The Nomological Network

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Page 1: The Nomological Network. What Is the Nomological Net? l An idea developed by Cronbach, L. and Meehl, P. (1955). Construct Validity in Psychological Tests,

The Nomological NetworkThe Nomological NetworkThe Nomological NetworkThe Nomological Network

Page 2: The Nomological Network. What Is the Nomological Net? l An idea developed by Cronbach, L. and Meehl, P. (1955). Construct Validity in Psychological Tests,

What Is the Nomological Net?What Is the Nomological Net?What Is the Nomological Net?What Is the Nomological Net?

An idea developed by Cronbach, L. and An idea developed by Cronbach, L. and Meehl, P. (1955). Construct Validity in Meehl, P. (1955). Construct Validity in Psychological Tests, Psychological Tests, Psychological Psychological BulletinBulletin, 52, 4, 281-302., 52, 4, 281-302.

Nomological is derived from Greek and Nomological is derived from Greek and means “lawful”.means “lawful”.

Links interrelated theoretical ideas with Links interrelated theoretical ideas with empirical evidence.empirical evidence.

Page 3: The Nomological Network. What Is the Nomological Net? l An idea developed by Cronbach, L. and Meehl, P. (1955). Construct Validity in Psychological Tests,

What Is the Nomological Net?What Is the Nomological Net?What Is the Nomological Net?What Is the Nomological Net?A representation

Page 4: The Nomological Network. What Is the Nomological Net? l An idea developed by Cronbach, L. and Meehl, P. (1955). Construct Validity in Psychological Tests,

What Is the Nomological Net?What Is the Nomological Net?What Is the Nomological Net?What Is the Nomological Net?A representation of the concepts (constructs) of

interest in a study,

ConstructConstruct

ConstructConstruct

ConstructConstruct

ConstructConstruct ConstructConstruct

Page 5: The Nomological Network. What Is the Nomological Net? l An idea developed by Cronbach, L. and Meehl, P. (1955). Construct Validity in Psychological Tests,

What Is the Nomological Net?What Is the Nomological Net?What Is the Nomological Net?What Is the Nomological Net?A representation of the concepts (constructs) of

interest in a study,

ConstructConstruct

ObsObs ObsObsObsObs ObsObs

ObsObs ObsObsObsObs ObsObs

ObsObs ObsObs

ConstructConstruct

ConstructConstruct

ConstructConstruct ConstructConstruct

...their observable manifestations,

Page 6: The Nomological Network. What Is the Nomological Net? l An idea developed by Cronbach, L. and Meehl, P. (1955). Construct Validity in Psychological Tests,

What Is the Nomological Net?What Is the Nomological Net?What Is the Nomological Net?What Is the Nomological Net?

A representation of the concepts (constructs) of interest in a study,

...their observable manifestations, and the interrelationships among and among these.

constructconstruct

ObsObs ObsObsObsObs ObsObs

ObsObs ObsObsObsObs ObsObs

ObsObs ObsObs

constructconstruct

constructconstruct

constructconstruct constructconstruct

Page 7: The Nomological Network. What Is the Nomological Net? l An idea developed by Cronbach, L. and Meehl, P. (1955). Construct Validity in Psychological Tests,

What Is the Nomological Net?What Is the Nomological Net?What Is the Nomological Net?What Is the Nomological Net?

ConstructConstruct

ObsObs ObsObsObsObs ObsObs

ObsObs ObsObsObsObs ObsObs

ObsObs ObsObs

ConstructConstruct

ConstructConstruct

ConstructConstruct ConstructConstruct

Theoretical Level: Concepts, IdeasTheoretical Level: Concepts, Ideas

Page 8: The Nomological Network. What Is the Nomological Net? l An idea developed by Cronbach, L. and Meehl, P. (1955). Construct Validity in Psychological Tests,

What Is the Nomological Net?What Is the Nomological Net?What Is the Nomological Net?What Is the Nomological Net?

ConstructConstruct

ObsObs ObsObsObsObs ObsObs

ObsObs ObsObsObsObs ObsObs

ObsObs ObsObs

ConstructConstruct

ConstructConstruct

ConstructConstruct ConstructConstruct

Theoretical Level: Concepts, IdeasTheoretical Level: Concepts, Ideas

Observed Level: Measures, ProgramsObserved Level: Measures, Programs

Page 9: The Nomological Network. What Is the Nomological Net? l An idea developed by Cronbach, L. and Meehl, P. (1955). Construct Validity in Psychological Tests,

PrinciplesPrinciplesPrinciplesPrinciples

ObsObs ObsObs ObsObs ObsObs ObsObs ObsObs

ConstructConstruct ConstructConstruct ConstructConstruct

Scientifically, to make clear what something is means to set forth the laws in which it occurs.

This interlocking system of laws is the Nomological Network.

Page 10: The Nomological Network. What Is the Nomological Net? l An idea developed by Cronbach, L. and Meehl, P. (1955). Construct Validity in Psychological Tests,

PrinciplesPrinciplesPrinciplesPrinciples

ObsObs ObsObs ObsObs ObsObs ObsObs ObsObs

ConstructConstruct ConstructConstruct ConstructConstruct

The laws in a nomological network may relate...The laws in a nomological network may relate...

observable properties or quantities to each other.

Page 11: The Nomological Network. What Is the Nomological Net? l An idea developed by Cronbach, L. and Meehl, P. (1955). Construct Validity in Psychological Tests,

PrinciplesPrinciplesPrinciplesPrinciples

ObsObs ObsObs ObsObs ObsObs ObsObs ObsObs

ConstructConstruct ConstructConstruct ConstructConstruct

The laws in a nomological network may relate...The laws in a nomological network may relate...

different theoretical constructs to each other.

Page 12: The Nomological Network. What Is the Nomological Net? l An idea developed by Cronbach, L. and Meehl, P. (1955). Construct Validity in Psychological Tests,

PrinciplesPrinciplesPrinciplesPrinciples

ObsObs ObsObs ObsObs ObsObs ObsObs ObsObs

ConstructConstruct ConstructConstruct ConstructConstruct

The laws in a nomological network may relate...The laws in a nomological network may relate...

theoretical constructs to observables.

Page 13: The Nomological Network. What Is the Nomological Net? l An idea developed by Cronbach, L. and Meehl, P. (1955). Construct Validity in Psychological Tests,

PrinciplesPrinciplesPrinciplesPrinciples

ObsObs ObsObs ObsObs ObsObs ObsObs ObsObs

ConstructConstruct ConstructConstruct ConstructConstruct

At least some of the laws in the network must involve observables.

Page 14: The Nomological Network. What Is the Nomological Net? l An idea developed by Cronbach, L. and Meehl, P. (1955). Construct Validity in Psychological Tests,

PrinciplesPrinciplesPrinciplesPrinciples

ObsObs ObsObs ObsObs ObsObs

ConstructConstruct ConstructConstruct ConstructConstruct

"Learning more about" a theoretical construct is a matter of elaborating the nomological network in which it occurs.

ObsObs ObsObs

Page 15: The Nomological Network. What Is the Nomological Net? l An idea developed by Cronbach, L. and Meehl, P. (1955). Construct Validity in Psychological Tests,

PrinciplesPrinciplesPrinciplesPrinciples

ObsObs ObsObs ObsObs ObsObs ObsObs ObsObs

ConstructConstruct ConstructConstruct ConstructConstruct

or of increasing the definiteness of its components.

"Learning more about" a theoretical construct is a matter of elaborating the nomological network in which it occurs...

ObsObs ObsObs

Page 16: The Nomological Network. What Is the Nomological Net? l An idea developed by Cronbach, L. and Meehl, P. (1955). Construct Validity in Psychological Tests,

PrinciplesPrinciplesPrinciplesPrinciples

ObsObs ObsObs ObsObs ObsObs ObsObs ObsObs

ConstructConstruct ConstructConstruct ConstructConstruct

The basic rule for adding a new construct or relation to a theory is that it must generate laws

(nomologicals) confirmed by observation...

ObsObs ObsObs

ConstructConstruct

Page 17: The Nomological Network. What Is the Nomological Net? l An idea developed by Cronbach, L. and Meehl, P. (1955). Construct Validity in Psychological Tests,

PrinciplesPrinciplesPrinciplesPrinciples

ObsObs ObsObs ObsObs ObsObs ObsObs ObsObs

ConstructConstruct ConstructConstruct ConstructConstruct

The basic rule for adding a new construct or relation to a theory is that it must generate laws

(nomologicals) confirmed by observation...

or reduce the number of nomologicals required to predict some observables.

ObsObs ObsObs

ConstructConstruct

Page 18: The Nomological Network. What Is the Nomological Net? l An idea developed by Cronbach, L. and Meehl, P. (1955). Construct Validity in Psychological Tests,

PrinciplesPrinciplesPrinciplesPrinciples

ObsObs ObsObs ObsObs ObsObs ObsObs ObsObs

ConstructConstruct ConstructConstruct ConstructConstruct

Operations that are qualitatively different "overlap" or "measure the same thing"...

Page 19: The Nomological Network. What Is the Nomological Net? l An idea developed by Cronbach, L. and Meehl, P. (1955). Construct Validity in Psychological Tests,

PrinciplesPrinciplesPrinciplesPrinciples

ObsObs ObsObs ObsObs ObsObs ObsObs ObsObs

ConstructConstruct ConstructConstruct ConstructConstruct

Operations which are qualitatively different "overlap" or "measure the same thing"...

if their positions in the nomological net tie them to the same construct variable.

Page 20: The Nomological Network. What Is the Nomological Net? l An idea developed by Cronbach, L. and Meehl, P. (1955). Construct Validity in Psychological Tests,

The Main Problem with the The Main Problem with the Nomological NetNomological Net

The Main Problem with the The Main Problem with the Nomological NetNomological Net

It doesn't tell us how we can assess the construct

validity in a study.