scaling Flashcards
What is meant by scaling? • Scaling theory • Person scaling versus Stimulus scaling – Differences between the two – Different scaling models • Methods based on the different scaling models – Guttman scalogram – Method of Equal Appearing Intervals – Method of Paired Comparisons
What is scaling?
- The process of measuring variables through a set of procedures needed to construct measuring devices.
- the “rules” used for assigning numbers to psychological variables by behavioural researchers
- An individual’s response to a stimulus is therefore quantified using such measuring devices.
What does scaling theory study?
How numbers are used in measurement.
Characteristics that we like our measurement to have
o Distinctiveness: number assignment that allows us to tell two stimuli apart (nominal scale)
o Order: number assignment that indicates the order of magnitude (ordinal scale)
o Quantity: the difference between two numbers is comparable (interval scale)
o Absolute zero: the number zero indicates an absence of that attribute (ratio scale)
characteristic of a nominal scale
Distinctiveness
characteristic of a ordinal scale
Distinctiveness + Order (Magnitude)
characteristic of an interval scale
Distinctiveness + Order (Magnitude) +Quantity (difference between 2 numbers is comparable)
characteristic of Ratio scale
Distinctiveness + Order (Magnitude) +Quantity (difference between 2 numbers is comparable)
+Absolute zero (number zero indicates an absence of the attribute)
What are the four types of scales in order of least to most information?
- Nominal
- Ordinal
- Interval
- Ratio
What is person scaling?
Measuring a person in terms of a particular attribute of interest to assess individual differences.
What is the purpose of person scaling?
To assess individual differences based on personal attributes.
What is the purpose of stimulus scaling?
To determine the magnitude of perceived characteristics of stimuli. - to which it reflects a certain construct or attitude
Who are the respondents in person scaling?
Random sample of individuals from the population.
Who are the respondents in stimulus scaling?
Subject Matter Experts (SMEs) carefully selected for their expertise.
What is the data analysis approach in person scaling?
Collapse across respondents to get the score for each respondent.
What is the data analysis approach in stimulus scaling?
Collapse across respondents’ judgment within a given stimulus to obtain a rating of each stimulus.
What scaling model is used for person scaling?
Likert scale.
What scaling model is used for stimulus scaling?
Thurstone scale.
What scaling model is used for both person and stimulus scaling?
Guttman scalogram analysis.
What distinguishes probabilistic models from deterministic models in scaling?
Probabilistic models allow measurement error; deterministic models do not.
What does a Likert scale measure?
An individual’s opinion or personality trait through agreement/disagreement on statements.
What is the method of equal-appearing intervals in Thurstone scaling?
Judges sort stimuli into categories with assumed equal intervals.
How are errant responses flagged in Thurstone scaling?
By eliminating judges who place 30% of statements into one category or show reversal in sorting.
What is the method of paired comparisons in Thurstone scaling?
Judges compare all possible pairs of stimuli to indicate preference.
What is the modal discriminant process in Thurstone scaling?
The most frequently occurring response for each stimulus.
In Guttman scaling, what does a unidimensional scale indicate?
All items are governed by a single underlying construct.
What is the index of reproducibility in Guttman scaling?
A criterion for deciding whether the scale is sufficiently unidimensional.
What is the purpose of selecting items in Thurstone scaling?
To cover the full range of the continuum with equally spaced scale values.
Fill in the blank: The difference between two stimuli in paired comparisons is represented by _______.
[Rd = R1 - R2]
True or False: Guttman scaling allows for measurement error.
False.
