Discussion Questions and
Topics (4)
Measurement and Scaling
1
Terms to know
• Operational definition
• Measurement of constructs
• Scaling types as tools:
– Nominal
– Ordinal
– Interval
– Ratio
2
What are the sources of variation in
measured score?
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True differences
Stability in individual characteristics
Transient factors
Situational Factors
Variations in administration
Sampling of items
Clarity of measurement instrument
Mechanical factors
3
Comment and Prove
• If a measure is valid, then it is reliable.
• X0=XT+XS+XR
– XO= Observed Score
– XT= True Score
– XS= Systematic Error
– XS= Random Erro
4
How doyou infer validity of a
measure?
• Indirect Evidence by reliability
– Where XR=0
• Direct evidence by validity
– Where XO=XT
• Domain Sampling Model
5
Test-retest
Indirect Evidence
Via Reliability
Coefficients
Alternate forms
Split half
Coefficient 
Predictive validity
Direct Evidence
Via Validity
Coefficients
Content validity
Construct validity
Convergent validity
Discriminant validity
6
What is the procedure for scale
development?
• Let’s look at Consumer Discontent Scale
and identify the steps in developing this
scale?
7