Lecture Slidesby

Dana B. Narter, Ph.D.

Research Methods in Psychology

Second Edition

Three Claims, Four Validities: Interrogation Tools for Consumers

of ResearchChapter 3

Chapter Overview

• Variables

• Three claims

• Interrogating the three claims using the four big validities

• Prioritizing validities

Variables

• Variables vs. constants

• Measured and manipulated variables

• From conceptual variable to operational definition

Measured and Manipulated Variables

• Measured variables are observed and recorded.

• Manipulated variables are controlled.

• Some variables can only be measured—not manipulated.

• Some variables can be either manipulated or measured.

From Conceptual Variable to Operational Definition

Operationalizing “Texting While Driving”

Three Claims

• Frequency claims

• Association claims

• Causal claims

• Not all claims are based on research.

Frequency Claims

• Frequency claims describe a particular rate or degree of a single variable.

• Frequency claims involve only ONE MEASURED VARIABLE.

Association Claims

• Association claims argue that one level of a variable is likely to be associated with a particular level of another variable.

• Association claims involve at least TWO MEASURED VARIABLES.

• Variables that are associated are correlated.

Positive Association

Negative Association

Zero Association

Making Predictions Based On Associations• Some association claims are useful because

they help us make predictions.

• The stronger the association between the two variables, the more accurate the prediction.

• Both positive and negative associations can help us make predictions, but zero associations cannot.

Causal Claims

Verbs for Association and Causal Claims

Not All Claims Are Based On Research

• Not all claims we read about in the popular press are based on research.

• Some claims are based on experience, intuition, or authority.

Interrogating the Three Claims Using the Four Big Validities• Interrogating frequency claims

• Interrogating association claims

• Interrogating causal claims

The Four Big Validities

Interrogating Frequency Claims

• Construct validity

• External validity (generalizability)

• Statistical validity

Interrogating Association Claims

• Construct validity

• External validity

• Statistical validity

Statistical Validity of Association Claims• Strength and significance

• Avoiding two mistaken conclusions– Type I error– Type II error

Table 3.5: Interrogating the Three Types of Claims Using the Four Big Validities

Interrogating Causal Claims

• Three criteria for causation– Covariance– Temporal precedence– Internal validity

Experiments Can Support Causal Claims• Experiment

• Independent variable

• Dependent variable

• Random assignment

When Causal Claims Are A Mistake

• Do family meals really curb eating disorders?

• Do early language skills reduce preschool tantrums?

Other Validities To Interrogate In Causal Claims• Construct validity

• External validity

• Statistical validity

Prioritizing Validities

• Which of the four validities is the most important?

• It depends on what kind of claim the researcher is making and what her priorities are.

This concludes the Lecture Slides for Chapter 3

Research Methods in Psychology Second Edition

byBeth Morling

For more resources to accompany this text, see wwnorton.com/instructors and everydayresearchmethods.com.