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. QualitativeMeasurement 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

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