1. Part Two
THE DESIGN OF RESEARCH
8-1

2. Chapter Eight
MEASUREMENT
8-2

3. Measurement
• Selecting observable empirical events
• Using numbers or symbols to represent
aspects of the events
• Applying a mapping rule to connect the
observation to the symbol
8-3

4. What is Measured?
• Objects:
– Things of ordinary experience
– Some things not concrete
• Properties: characteristics of objects
8-4

5. Characteristics of Data
• Classification
• Order
• Distance (interval between numbers)
• Origin of number series
8-5

6. Data Types
Order Interval Origin
Nominal none none none
Ordinal yes unequal none
Interval yes equal or none
unequal
Ratio yes equal zero
8-6

7. Sources of Measurement Differences
• Respondent
• Situational factors
• Measurer or researcher
• Data collection instrument
8-7

8. Validity
• Content Validity
• Criterion-Related Validity
– Predictive
– Concurrent
• Construct Validity
8-8

9. Reliability
• Stability
– Test-retest
Equivalence
– Parallel forms
• Internal Consistency
– Split-half
– KR20
– Cronbach’s alpha
8-9

10. Practicality
• Economy
• Convenience
• Interpretability
8-10