measurement student

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Measurement

Assigning Numbers ToReflect the Degree or

Amount of a Characteristic



Measurement Scales

Series of items thatare arrangedprogressively

according to value ormagnitude

A series into which anitem can be placeaccording to itsquantification



Be Careful«.

The type of scale used will dictate:

the type of analysis that can be done

the conclusions that can be drawn



MEASURES OF

CENTRAL TENDENCY

MODE:

MEDIAN:

MEAN:



Nominal Scale

Identification only

No order or meaning

to the numbers

Examples:

Measure of CentralTendency:



Ordinal Scale

Order to the data

Distance between twonumbers is unknown and

uneven

Examples:

Measure of CentralTendency:



Interval Scale

Order to the data

Equal distance betweennumbers

No ³natural zero´

Examples:

We assume a lot of scales areinterval

Measure of Central Tendency:



Ratio Scales

Order to the data

Equal distance between numbers

³natural zero´ where zero means ³none´

Examples:

Measure of Central Tendency:



YOUR TURN --Write a question for

each type of scale

Nominal

Ordinal

Interval

Ratio



Converting Theories into Measurement

Instruments

Theory ± establishes the relationshipamong constructs

The constructs must be related to observable

data

C

C

CObservable data

M

M

M



Need to convert the conceptual

definition to an operational definition:

Conceptual definition:

Operational Definition:



Example: Operationalizing Consumer

Sentiment Toward Marketing

ProductQuality

Price of

Products

Ads forproducts

Retailing

The quality of most products that I buy today is as goodas can be expected

I am satisfied with most of the products I buy«

Most products I buy are overpricedMost prices are reasonable considering the high cost of

doing business«

Most advertising provides consumers with essentialinformation

Most advertising is annoying®«

Most retail stores serve their customers well

Because of the way retialers treat me most of myshopping is unpleasant® «.

Gaski and Etzel ³Index of consumer sentiment toward marketing´ in Marketing Scales Handbook (2000)



Criteria For Good Measurement

R eliability-

Validity-

Sensitivity-



1) Reliability of Scales

Internal Consistency: Coefficient alpha (inter-correlation

among items)

Are the results on questions measuringthe same thing consistent?

Single item scales more suspect torandom error

Test/retest: Are consistent results found on repeated

measures

Inter-judge reliability Agreement between coders/ judges

evaluating an ob ject

NOTE: Reliability is a

necessary condition for

validity but a

reliable instrument may not

be valid



2 ) Validity of Scales

Content validity (Face validity) Everything related to the construct is captured by the instrument

Construct Validity Does the measure actually measure the construct, concept or trait that

it is suppose to be measuring

Look at ± convergent validity, discriminant validity, nomologicalvalidity

Pragmatic (Predictive) validity Do the results of the measurement predict some other characteristic

or behavior



3 ) Sensitivity Refers to an instruments ability to accurately measure variability

in stimuli or responses

Example:

I love to eat chocolate:

Agree Disagree

OR

Strongly agree Mildly agree Neither agree or disagree Mildly disagree Strongly disagree



Types of Scales



General Distinction:

Dichotomous Scale:

Multichotomous Scale:

Open-ended Ratio:

Open-ended Nominal:



Continuous Graphic Rating Scales

Place a mark on the line indicating how importantit is to have each of the following at yourvacation resort:

Alpine slides _____________________unimportant important

5 inch line 127 mm

1/20 inch

Scaling?



Other Graphic Rating Scales

Happy faces

Thermometer

Uses??



Itemized Rating Scale (Category

Scales ) Several categories from which the respondent

can choose

Example of a General Itemized rating scale:

How likely are you to buy a Sony DVD player in the next 3mos.

definitely will buy

Probably will buy Might buy

Probably will not buy

Definitely will not buy



Common Forms of Itemized Rating

Scales:

Likert

Semantic Differential

Staple



Likert Scales

Sentences with which the respondentagrees or disagrees

Indicate your level of agreement ordisagreement with the followingstatement:

It would be cool to have a candy-red 1965convertible Mustang

SD D Neither A SA



Likert Scales

Code such that higher numbers indicatemore or better things

May need to Reverse Code

Can create summated scales to form anindex if the coefficient alpha is high

Assume __________ scale



EXAMPLE of LIK ERT SCALES

PLEASE ³X´ ONE BOX FOR EACH STATEMENT BELOW. STRONGLY STRONGLY

DISAGREE AGREE

I really want my heart to get better ««««««««««««««..

I would be very happy if my heart got better««««««««««...

I desire that my heart gets better «««««««««««««««.

It is important to me that my heart gets better««««««««««

Whether or not my heart gets better doesn¶t really matter tome«...

I feel like my heart is not as healthy as I would like«««««««..

I have been without a healthy heart for a long time«««««««.

1 2 3 4 5

1 2 3 4 5

1 2 3 4 5

1 2 3 4 5

1 2 3 4 5

1 2 3 4 5

1 2 3 4 5




Series of attitude scales where repeated judgments about a concept are made

Opposite ad jective words or phrases

Use several of these and sum them if thecoefficient alpha is high

Fast __:__:__:__:__:__:__ SlowBad __:__:__:__:__:__:__ Good

Service Service

Tasty __:__:__:__:__:__:__ Not Tasty

Food Food




Code such that higher numbers indicatebetter things or more of something May need to Reverse Code

Make an overall score--sum the items

Develop a snake diagram (image profile)

to compare competitors

Assume _____ scaling



Staple Scale

Use +5 (describes completely) to -5 (does notdescribe at all)

Easy to construct

Good for phone

May look difficult for respondentService is Fast -5 -4 -3 -2 -1 +1 +2 +3 +4 +5

Food is Tasty -5 -4 -3 -2 -1 +1 +2 +3 +4 +5

Assume _______ scaling



Considerations for Itemized

Response Scales 7 +/- 2 categories work best

Odd vs even number scales

Equal number of positive and negative categories

Consider ³r ever se scaling´ but use sparingly

Distinguish ³u

ndecided ́ from ³neu

t r al ́

Put ³undecided´ or ³no opinion´ at the end



Comparative Scales

Compare one set of ob jects directly withanother

sensitive

easy

can create artificial differences



Paired Comparison

Which do you prefer? Barry Manilow

Red Hot Chili Peppers

Barry Manilow Tom Petty

Tom Petty

Red Hot Chilli Peppers



Paired Comparison Table (Cross Tab )

Manilow RHCP Tom Petty

Manilow ----- 0.90 0.85

RHCP 0.10 ---- 0.60

Tom Petty 0.15 0.40 ----

* % of time that the column was chosen over therow



Calculation of ´Rank-Order Valuesµ

Manilow RHCP Tom Petty

Manilow - 1 1

RH

CP 0 - 1

Tom Petty 0 0 -

0 1 2

*If the % score was 50% or more = 1

*If the % score was less than 50% = 0

Higher score indicates greater preference



Rank-order Scales

Respondents are simultaneously presentedwith several ob jects/attributes that theyrank order

Please rate the following from 1=mostpreferred/important to 4= leastpreferred/important

price location

cleanliness food selection



Rank-order Calculations

Calculate frequencies of responses for each item

Multiply frequency by response

Lower numbers indicate greater preference

See Example - Handout



Comparative Continuous Graphic

Rating Scale Similarity ratings used for perceptual

maps

Pitt and WVU

_________________________

Exactly Completely

the same different



Constant Sum Scales

Assign chips or points toattributes

Very careful withinstructions

Difficult for the respondent

use with highinvolvement/education

measurement student

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