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This article provides an in-depth review of operational definitions and how they are used in research methods for advertising and public relations. It covers the process of translating abstract concepts into concrete variables, different levels of measurement, and scales for measuring human behaviors.
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Research Methods in AD/PR COMM 420 Section 8 Tuesday / Thursday 3:35 pm -5:30 pm143 Stuckeman Nan Yu 2007 Fall_COMM 420_Week 4(2) @ NY 1
A review • Operational Definitions • Variables
Operational Definition • Answers the question: How do we know? • It translates the concept into simplified terms that can be measured.
Operational Definition (cont.) • How can an abstract concept be transformed into a concrete variable that can be studied (measured)? • How can it be empirically defined?
Operational Definition (cont.) Academic Performance Final grades Class participation Term papers
Operational definition (cont.) attention recall eye movement response speed
Operationalization • Links concepts to variables Abstract Concepts Concrete Variables
Relationships Between Variables One way to operationalize each concept: Theory Academic performance (Concept Y) Intelligence (Concept X) Hypothesis IQ score (Variable X) GPA (Variable Y)
IV and DV • independent variable • predictor (cause) variable • antecedent variable • dependent variable • criterion (effect) variable Hypothesis IQ score (Variable X) GPA (Variable Y)
Intervening Variable • Comes in between the IV and DV • Usually offers an explanation of why or how the IV affects the DV • E.g., Exposure to TV commercials leads to changes in attitude towards the advertised product, which in turn lead to product sales. Changes in attitude towards advertised product Exposure to TV commercials Product sales DV IV Intervening Variable
Rules • IV can be manipulated or measured. • DV are always measured.
Example IV: Brand image (manipulated) DV: Purchase intention (measured)
Example (cont.) IV: Body type (manipulated) DV: Perceived body type (measured)
2007 Fall_COMM 420_Week 4(1) @ NY Measurements temperature length Amount of fluid weight
2007 Fall_COMM 420_Week 4(2) @ NY How do we measure human behaviors?
2007 Fall_COMM 420_Week 4(1) @ NY What are measurements? The process of assigning numbers to observations according to specified rules.
Levels of Measurement:Nominal (Categorical) • Nominal (Categorical) • Differentiated based on type or category • Very commonly seen in demographic data: • Gender (1=male, 2=female) • Political party affiliation (1=democrat, 2=republican, 3=independent).
Nominal (Categorical) • Categories are mutually exclusive • Categories are exhaustive, otherwise they will not represent the variable fully • E.g., One individual case should fit in at least one category
Levels of Measurement: Ordinal • Ordinal: values can be rank ordered. • Social status (1=low, 2=middle, 3=high) • Household incomes • 1. Less than $ 20,000 • 2. $20,001 to $30,000 • 3. $30,001 to $45,000 • 4. $45,001 to $60,000 • 5. $60,001 to $80,000 • 6. $80,001 to $100,000 • 7. More than $100,000 • Ordinal measures provide orders (2 is more than 1), but do not tell how much apart the values in different categories are.
Levels of Measurement: Interval • If distances between categories are equal, we can say it interval variable. We assume that the distance between a 1 and 2 is the same as the distance between 2 and 3.
Levels of Measurement: Ratio • Same attributes as interval variables, plus a meaningful zero point. • Height: 6-foot man is twice as tall as a 3-foot boy. • Age: 20-year-old boy is twice as old as a 10-year-old boy. • Temperature: 100 degree is twice as hot as 50 degree • Time: 30 minutes is three times as long as 10 minutes. • Ration measures mean that a 2 is twice as much of something.
Level of Measurements (cont.) • Interval and ratio variables • continuous variables. • more precise • more powerful statistical analysis could be applied
Scales of Measurement: Likert-type Scale (p.153-154) • Indicate on the scale below, how strongly you agree or disagree with the statement: Listening to heavy metal music makes one prone to violent acts. __Strongly agree __Agree __Neutral __Disagree __Strongly disagree OR Listening to heavy metal music makes one prone to violent acts. Strongly disagree Neutral Strongly agree -4 -3 -2 -1 0 1 2 3 4
Semantic Differential (Bipolar) • Similar to Likert-type scales, but involves pairs of attributes based on which the respondent will judge something. • E.g., Indicate on the scale below, circling only one dot, how you feel about the web site you have just seen: Organized * * * * * * * Unorganized Confusing * * * * * * * Not Confusing
Thurstone Scales Generating Potential Scale Items.
Thurstone Scales (cont.) Rating the Scale Items.
Thurstone Scale Now, you have to select the final statements for your scale. You should select statements that are at equal intervals across the range of medians.
Open-ended questions • What is your age? • How long have you been using Internet? • Provide ideas about how to develop measurements. Often used during interviews or focus groups.
Other scales • Guttman Scales • Thermometer Scaling • Multidimensional Scaling • Unobtrusive measures
Unit of Measurement/Observation • unit of measurement (observation) • Smallest unit used for purposes of observation (e.g., individual, group, news story, etc.).
Unite of Analysis • unit of analysis = Smallest unit used for data analysis.
Example • E.g., In a survey, we ask (measure) the annual income of each individual in a household, but in the analysis we might be interested in the average income per household. • What is the unit of observation/analysis in this case?
Decisions in the Measurement Process • Any existing measures of the variables of interests? • What is the unit of observation (individuals, social groups, stories, etc.)? • Who measures (self-report, other-report, researcher, etc.) whom (sampling)? • What levels/types of measurements do you use (e.g. interval? Likert-type)?
Measurement Error • All measurements are subject to error • Two types of measurement error: • Systematic error (due to instrument calibration) • Constant and predictable • Random error • Erratic and unpredictable
Pilot test (pre-test) • A test before the formal research is conducted • Test the stimulus • Test the measurement instruments • Eliminate potential problems • Reduce predictable errors • It’s like a mini test to make sure everything goes well as you expected. The sample could be a lot smaller than the actual sample. But you can not include the same person in both.
In-class Demo • Please go to this website • http://www.personal.psu.edu/mbo1/forms/survey1/survey1.html • Down load the file “in-class demo”
In-class Demo (cont.) • Click and answer all questions that are on the questionnaire. • Identify the level of measurement of each PART • Submit your answers to ANGEL (week 4, drop box for in-class Demo)