Measurement Neuman and Robson Ch. 6
What is it? The process of creating measurable concrete variables from abstract concepts Extends the senses (empirical) Tends to be more of a concern for quantitative researchers
Quantitative vs. Qualitative Measurement Differences Timing Type of data collected Linkage of concepts to data (pre-planned vs. reflective/interactive)
The Measurement Process Quantitative = deductive Qualitative = inductive Both involve conceptualization and operationalization
Steps identify concept of interest develop conceptual definition decide on units of analysis operationalize to create a variable links concept to measurement technique
Process of Quantitative Operationalization:
Process of Qualitative Operationalization: Empirical Observations Working Ideas Concepts Generalizations/Theories
Reliability and Validity Reliability = the consistency or dependency of a measure Does the measure consistently give the same results? Validity = truthfulness of a measure Is it measuring what the researcher thinks it is measuring?
Types of Reliability inter-observer inter-item test-retest parallel forms
Improving Reliability Clear conceptualization Use of most precise (or highest) level of measurement possible Use of multiple indicators Use of pretests, pilot studies, replication
Validity face validity content validity criterion validity Predictive validity Concurrent validity
Relationship Between Reliability and Validity
Internal and External Validity Internal Validity Can alternative explanations for change in the dependent variable be eliminated? External Validity Generalizability Statistical Validity Was the correct test used?
Quantitative Variable Construction: a) Continuous vs. Discrete categories b) Levels of measurement: nominal ordinal interval/ratio
Scale or Index Construction Composite Measures Index vs. Scales Mutually exclusive and exhaustive attributes Unidimensionality Reproducibility
Common Scales and Indexes Likert Scale Bogardus Social Distance Scale Semantic Differential Guttman Scale Click Here for more detail on measurement. Click Here