Chapter 12 & 13 - Measurement of Variables Flashcards
Four levels of measurement
Nominal
Ordinal
Interval
Ratio
Categorical levels of measurement
Nominal
Ordinal
Continuous levels of measurement
Interval
Ratio
Nominal level of measurement
Identification; classification
Ordinal level of measurement
Ranking of categories, but not equidistant (at equal distances)
Interval level of measurement
- Equidistant (at equal distances) ranking, but zero point not fixed
- Likert-type scales: Ordinal or interval?
Ratio level of measurement
Possesses a unique origin (zero point)
Rating Scale Formats
– Dichotomous/binary scale
– Category scale
– Semantic differential scale
– Numerical scale
– Itemized rating scale
– Likert-type scale
– Fixed or constant sum scale
– Stapel scale
– Consensus scale
– Graphic rating scale
– Paired comparison scale
– Forced choice scale
– Comparative scale
Dichotomous/binary scale rating scale example
Yes vs. No
Category scale rating scale example
English; French; Other
Semantic differential scale rating scale example
Good —– Bad; Emotionally stable —– Neurotic
Numerical scale rating scale example
Responsive 1 2 3 4 5 6 7 Unresponsive
Itemized rating scale rating scale example
Can be balanced or unbalanced; forced or unforced
Likert-type scale rating scale example
Fixed or constant sum scale rating scale example
distributing 100 points across several items (need to add
up to 100)
Stapel scale rating scale example
-3 -2 -1 Interpersonal skills +1 +2 +3
Consensus scale rating scale example
Developed by consensus by a panel of judges
Graphic rating scale rating scale example
Paired comparison scale rating scale example
Respondents asked to choose between two objects at a time
(among a small number of objects)
Forced choice scale rating scale example
Ranking objects among the provided alternatives
Comparative scale rating scale example
Provides a point of reference to assess attitudes toward a
particular object/event/situation
Response-scale format considerations
– Measurement scale (nominal, ordinal, interval, ratio)
– Number of scale points/categories
* Need to be mutually exclusive and collectively exhaustive
– Balanced or unbalanced scales
* Equal # of favourable & unfavourable categories?
– Forced or non-forced choice
* “Neutral” category
* Odd or even number of categories
– Category labels for scales (anchors)
* Verbal; numerical; unlabeled (e.g., graphic)
– Number of items in a scale
Operationalization of variables
Breaking an abstract construct down to its measureable or
tangible components
* Can tap into a construct by looking at the behavioural dimensions, facets, and properties denoted by the construct and translating them into observable/measurable elements
Delineating the antecedents, consequences, or correlates of the construct is not _______________
operationalization
Steps in the Operationalization of variables
- Clear definition of the construct (and possibly its dimensions)
- Develop a pool of items (indicators or elements) representing more concrete manifestations or operalizations of the construct
- Choose a response format (e.g., Likert-type scale)
- Collect data from a (representative) sample
- Conduct item analyses and select items for the scale(s)
- Test the reliability and validity of the scale(s)
Typical process in Developing Scales
– Define the concept to be measured
– Identify components/elements of the concept
– Specify sample of observable, measurable items representing the components/elements of the concept
– Select an appropriate response format to measure the items
– Combine the items into a composite (summated) scale
– Pretest the scale to assess respondent understanding
– Assess scale reliability and validity
– Revise the scale (if needed)
considerations for evaluating existing scales
– Title, author(s), publisher (if applicable)
– Language(s); equivalence of translated forms
– Construct(s) (allegedly) measured
– Characteristics of development/normative sample(s)
– Costs/permissions required
– User qualifications
– Format; administration method; scoring; length/time
– Psychometrics: Evidence of reliability, validity, fairness
– Independent reviews or peer-reviewed research
____________ Consist of a number of closely related
items (questions or statements) whose
responses are combined into a composite
score to measure a construct
Multi-Item (Summated) Scales
Recommendations for Multi-Item (Summated) Scales
Items should be closely related, represent only
a single construct, and represent the construct
completely
Assessing Measurement Scales
Reliability
Validity (unitary)
Assessing Measurement Scales - Reliability
- Test-retest reliability
- Parallel-form reliability
- Inter-rater reliability
- Internal consistency reliability
- Split-half reliability
Assessing Measurement Scales - Validity (unitary)
- Content validity
- Construct validity
- Convergent validity
- Discriminant validity
- Criterion-related validity
- Concurrent validity
- Predictive validity
Reliability
the stability and consistency of scores generated by a scale
Stability of scores (derived from scales)
– Test-retest reliability (stability over time)
– Parallel-form reliability (stability across forms)
– Administer them to the same subjects
– Inter-rater reliability (stability across raters)