Part Two THE DESIGN OF RESEARCH McGraw-Hill/Irwin © 2003 The McGraw-Hill Companies, Inc.,All Rights Reserved.

Chapter Eight MEASUREMENT

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

What is Measured? Objects: Properties: characteristics of objects Things of ordinary experience Some things not concrete Properties: characteristics of objects

Characteristics of Data Classification Order Distance (interval between numbers) Origin of number series

Data Types Order Interval Origin Nominal none none none Ordinal yes unequal none Interval yes equal or none unequal Ratio yes equal zero

Sources of Measurement Differences Respondent Situational factors Measurer or researcher Data collection instrument

Validity Content Validity Criterion-Related Validity Predictive Concurrent Construct Validity

Reliability Stability Equivalence Internal Consistency Test-retest Parallel forms Internal Consistency Split-half KR20 Cronbach’s alpha

Practicality Economy Convenience Interpretability