Introducing Communication Research 2e © 2014 SAGE Publications Chapter Five Measurement: Research Using Numbers

Key Concepts NOIR – nominalordinal intervalratio 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 & Reliability Measures 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 Agree Agree Neutral DisagreeDisagree 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----Weak Expensive---Cheap Beautiful- --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 Coding Concurrent validity Construct validity Content validity Convergent validity Correlation Criterion validity Divergent validity Established measures reliability Expert validity Face validity Internal reliability Interitem reliability Intercoder or observer reliability Interval Likert scale Measurement Nominal Numbers Numerals Ordinal Panel validity Phrenologist Predictive validity Rank order questions Ratio Reification Reliability Reliability coefficient Scale Semantic differential “Split half” technique Test-retest Validity Introducing Communication Research 2e © 2014 SAGE Publications