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Introducing Communication Research 2e © 2014 SAGE Publications
Chapter FiveMeasurement: Research Using Numbers
Key Concepts
•NOIR –nominal ordinalinterval ratio
•Reliability•Validity•Scales •Numerals - labels such as zip codes•Numbers - can be computed
Introducing Communication Research 2e © 2014 SAGE Publications
“N-O-I-R”
Measures can be -•Nominal - labels
•Ordinal - rank order
•Interval - numeric scale
•Ratio - numeric scale with a zero point.
Introducing Communication Research 2e © 2014 SAGE Publications
“N-O-I-R” Examples
•Nominal - press, radio, television
•Ordinal - freshman, sophomore, junior
•Interval - age (years): __ 0–4 __ 5–9 __ 10–14
•Ratio - age in years ____
Introducing Communication Research 2e © 2014 SAGE Publications
Validity & ReliabilityMeasures must have –
•Validity – ▫measure what they are supposed to
measure.and
•Reliability –
▫perform consistently.
Introducing Communication Research 2e © 2014 SAGE Publications
Assessing Reliability of Measures
•Test - retest.
•Split half.
•Intercoder or observer reliability.
Introducing Communication Research 2e © 2014 SAGE Publications
Assessing Validity of Measures• Content or ‘face’ - “looks OK.”
• Expert or panel - “looks OK’” to experts.
• Construct - theoretically OK.
• Convergent - agrees with similar measures.
• Divergent - low agreement with different measures.
• Predictive - predicts “real world” outcomes.
Introducing Communication Research 2e © 2014 SAGE Publications
Likert Scale
Strongly Strongly Agree Agree Neutral Disagree Disagree
1. Hybrid vehicles are powerful.
___ ____ ____ ____ _____ 2. Hybrid vehicles reduce dependency on foreign oil.
___ ____ _____ ____ _____
Introducing Communication Research 2e © 2014 SAGE Publications
Semantic Differential Scale
The XKJ Bogbuster 300 is
Powerful - - - - WeakExpensive - - - CheapBeautiful - - - Ugly
Introducing Communication Research 2e © 2014 SAGE Publications
Proprietary Measures
•Tests and measures developed as commercial products.
•Copyright.•May not be used without permission.
Examples - ▫SATs▫GREs▫vocational tests
Introducing Communication Research 2e © 2014 SAGE Publications
Chapter Summary
•Measures must have –▫Validity and reliability.
•Measures exist at four levels – ▫ nominal — ordinal — interval — ratio.
•Two common scales – ▫Likert ▫semantic differential.
Introducing Communication Research 2e © 2014 SAGE Publications
Vocabulary Review
Introducing Communication Research 2e © 2014 SAGE Publications