11

Research Methods in AD/PR

COMM 420Section 8

Tuesday / Thursday 3:35 pm -5:30 pm

143 Stuckeman Nan Yu

2007 Fall_COMM 420_Week 4(2) @ NY

2

A review

Operational Definitions Variables

3

Operational Definition

Answers the question: How do we know?

It translates the concept into simplified terms that can be measured.

4

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?

5

Operational Definition (cont.)

Academic Performance

Final grades

Term papers

Class participation

6

Operational definition (cont.)

attention

eye movement

response speed

recall

7

Operationalization

Links concepts to variables

Abstract Concepts

Concrete Variables

8

Relationships Between Variables

One way to operationalize each concept:

Intelligence (Concept X)

Academic performance (Concept Y)

IQ score (Variable X)

GPA (Variable Y)

Theory

Hypothesis

9

IV and DV

independent variable predictor (cause) variable antecedent variable

dependent variable criterion (effect) variable

IQ score (Variable X)

GPA (Variable Y)

Hypothesis

10

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.

Exposure to TV

commercials

Changes in attitude towards

advertised product

Product sales

IVDV

Intervening Variable

11

Rules

IV can be manipulated or measured. DV are always measured.

12

Example

IV: Brand image (manipulated)DV: Purchase intention (measured)

13

Example (cont.)

IV: Body type (manipulated)

DV: Perceived body type (measured)

14

How do we measure variables?

15

Measurements

2007 Fall_COMM 420_Week 4(1) @ NY

length

weight Amount of fluid

temperature

16

2007 Fall_COMM 420_Week 4(2) @ NY

How do we measure human behaviors?

17

What are measurements?

2007 Fall_COMM 420_Week 4(1) @ NY

The process of assigning numbers to observations according to specified rules.

18

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).

19

Nominal (cont.)

20

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

21

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.

22

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.

23

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.

24

Levels of Measurement (cont.)

25

Level of Measurements (cont.)

Interval and ratio variables continuous variables. more precise more powerful statistical analysis could be applied

26

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

27

Likert-type scale (cont.)

28

Likert-type scale (cont.)

29

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 * * * * * * * UnorganizedConfusing * * * * * * * Not Confusing

30

Semantic Differential Scales (cont.)

31

Thurstone Scales

Generating Potential Scale Items.

32

Thurstone Scales (cont.)

Rating the Scale Items.

33

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.

34

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.

35

Other scales

Guttman Scales Thermometer Scaling Multidimensional Scaling Unobtrusive measures

36

Unit of Measurement/Observation

unit of measurement (observation) Smallest unit used for purposes of

observation (e.g., individual, group, news story, etc.).

37

Unite of Analysis unit of analysis = Smallest unit used

for data analysis.

38

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?

39

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)?

40

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

41

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.

42

In-class Demo

Please go to this website http://www.personal.psu.edu/mbo1/fo

rms/survey1/survey1.html Down load the file “in-class demo”

43

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)