Copyright © Houghton Mifflin Company. All rights reserved.Chapter 4 | 1 Measurement Turning “Conceptual” variables: –The ideas that form the basis of a

Copyright © Houghton Mifflin Company. All rights reserved. Chapter 4 | 1

Measurement

• Turning “Conceptual” variables:

– The ideas that form the basis of a research hypothesis

– INTO –

• “Measured” variables

– Numbers that represent conceptual variables


Conceptual and Measured Variables in a Correlational Research Design


Operational Definition

• Operational definition – a precise statement of how a conceptual

variable is turned into a measured variable


Converging Operations

• Converging operations – We use different operationalizations of the

same conceptual variable to triangulate (hone in) on the conceptual variable

– How might you “converge” on the conceptual variable “attraction” ? Write two operational definitions for the variable.


Operational Definitions


Types of variables

• Nominal variable – Used to name or identify a particular

characteristic (e.g., sex, religion)

• Quantitative variable– Uses numbers to indicate the extent to

which a person possesses a characteristic (e.g., shyness, intelligence)


Types of Measurement Scales

• Interval scale – Equal distances between scores on a measure are

known to correspond to equal changes in the conceptual variable (e.g., Fahrenheit)

• Ratio scales – Interval scales that also have a true zero point

• Ordinal scale (most common in behavioral research) – Numbers indicate whether there is more or less of

the conceptual variable, but do not indicate the exact interval between the individuals on the conceptual variable (e.g., rating scales)


Measures

• Self-report vs. behavioral

• Self-report measures– Free-format vs. fixed format (next slide)


Free-Format Self-Report Measures

• Free-format self-report measures – Allow respondents to indicate whatever thoughts

or feelings they have about the topic, without any constraints imposed (e.g., projectives)

– Produce a rich set of data– Very difficult and time-consuming to turn the

generated thoughts into a set of measured variables

– Hard to compare individuals


Fixed-Format Self-Report Measures

• Fixed-format self-report measures – The individual is presented with a set of

questions called items combined into a scale

– Likert scale (most popular) -- consists of a series of items that indicate agreement or disagreement with the issue that is to be measured

– Your homework assignment


Acquiescent Responding

• Acquiescent responding – May occur if all the items on a Likert scale

are phrased in the same direction– Not possible to tell if the respondent is

simply tending to agree with everything or if he or she really agrees with the content of the item


Semantic Differential

• Semantic differential – The topic being evaluated is presented

once at the top of the page– Items consist of pairs of adjectives located

at the two endpoints of a standard response format


Reactivity

• Reactivity – Changes in responding that occur when

individuals know they are being measured– Example: Social desirability -- tendency to

present self in a positive or socially acceptable way to the researcher


Behavioral Measures

• Measure behavior directly

• Types of behavioral variables include:– Frequency, Duration, Intensity, Latency, Speed– See Table 4.5– Psychophysiological measures

• Advantages / Disadvantages?– nonreactive

Documents

Copyright © Houghton Mifflin Company. All rights reserved.Chapter 4 | 1 Measurement Turning “Conceptual” variables: –The ideas that form the basis of a