copyright © houghton mifflin company. all rights reserved.chapter 4 | 1 measurement turning...
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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
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Conceptual and Measured Variables in a Correlational Research Design
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Operational Definition
• Operational definition – a precise statement of how a conceptual
variable is turned into a measured variable
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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.
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Operational Definitions
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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)
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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)
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Measures
• Self-report vs. behavioral
• Self-report measures– Free-format vs. fixed format (next slide)
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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
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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
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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
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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
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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
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Behavioral Measures
• Measure behavior directly
• Types of behavioral variables include:– Frequency, Duration, Intensity, Latency, Speed– See Table 4.5– Psychophysiological measures
• Advantages / Disadvantages?– nonreactive