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