scaling and scoring procedure and analysis

8/13/2019 SCALING AND SCORING PROCEDURE AND ANALYSIS

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Scaling describes theapplication of numbers, or

judgments that are converted to

numerical values, to describe

the perceived intensity of asensory experience or degree of

liking or disliking for some

experience or product.


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The vital importance of

knowing the properties and

limitations of a measuring

instrument can hardly bedenied by most natural

scientist. However, the use of

many different scales for

sensory measurement iscommon within food science;

but very few of these have

ever been validated

Land and Shepard 1984


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What was subjective and

private becomes public

data. The data arequantitative; basis of

scaling.


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Methods of scaling involve

the application of numbers

to quantify sensoryexperiences through the

process of numerification

that sensory evaluationbecomes a quantitative


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Scaling involves sensing

a product or stimulus andthen generating a

response that reflects

how the person

perceives the intensity

or strength of one or

more of the sensations

generated by thatproducts


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Stimulus Response

Psychological Process

Psychological translation of energy in the outside

world into sensation


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Stimulus Sensation Response

Judgment

Process

Psychophysical

process

PSYCHOPHYSICAL MODEL

translation of that experiences into some responses


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Psychophysical model statesthat as the physical strength of

the stimulus increases the

sensation will increase in someorderly way.


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Scaling

- tool used for showing differences and degrees

of differences among products

If the products are very similar and there is a

question of whether there is any difference at all,discrimination testing methods are more suitable


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Scenarios:

a. Untrained Observer/PanelistPresuming:

1. They understand and the attribute they

are asked to scale.

2. There is no need to train or calibrate themto use the scale.


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b. Trained Panelist- trained to insure a uniform

understanding of the attribute

involved.

- calibrated with referencestandard to illustrate what is a

little and what is a lot of this

attribute- focus on the product.


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According to Fechner and other

referred scaling as the method of

single stimuli and considered less

reliable than the choice method.


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Theories:

1.Measurement Theory

2.Line Scaling

3.Magnitude estimation4.Category-Ratio Scale/Labeled

magnitude scale

5.Relative Scaling


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Measurement Theory

- study of the pattern of response magnitudes

to establish which scale properties areinvariants

- tells that numbers can be assigned to items

in different ways:

a. Nominal scalingb. Ordinal scaling

c. Interval scaling

d. Ratio scaling


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Nominal scaling

- numbers are assigned to eventsmerely as label- analysis of such data is to make

a frequency counts.

- whether they are belong to thesame categories or to different

ones.

Example:

1-female

2-male


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Nominal scaling

Uses

- Classification testStrength

-quick way to get preliminary

informationWeakness

- terms are not standardized

-confusion with untrained panelist

Data AnalysisTallying frequency


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Ordinal scaling

-number are assigned to recognize

the rank order of the product s withregard to some sensory property,

attitude or opinion

Usescreening three or more

products for a specific properties


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Strength-rapid and required relatively

little training/orientation

Weakness-doesnt provide any

information about the amount of

difference for the product attributes

Data Analysis

Friedmans rank sum test

ANOVA


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Interval Scaling

Weakness:

Include range effects that relate to

the tendency of judges to give

different rating for an attribute

(small)

Data analysis-t-test (two product)- ANOVA (more than two products)


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Weakness

a. Confusing

b. Tendency to be measured from

bidirectional hedonic response

Data Analysis

Log transformation of normalized

data.


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Line Scaling

-second widely used for intensity

scaling- making a mark or slash on a line to

indicate the intensity of some attribute

Weakness:1. Tendency for panelist to ignore both

ends of the scale.

2. Use only the middle categories


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Magnitude estimation

- popular techniques for reading

in psychophysical studies.

Example:

If product A is given the value of 20

for sweetness intensity and product B

seems twice as sweet, B is given a

magnitude estimate of 40.


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Magnitude estimation

Two variation:

a. standard stimulus is givento the subject as reference and

that standard is assigned a

fixed value.

b. Non modulus magnitudeestimation is given and the

participant is free to choose

any number he wishes for thefirst sample.


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Labeled magnitude scale

-attempt to provide ratio information, but combines

it with common verbal description along a linescale to provide a single frame of reference.

- involve a horizontal or vertical line liberate

spaced label and the panelists table is to make a

mark somewhere along the line to indicate thestrength of their perception or strength of likes or

dislikes


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Relative scaling

-Consumer has a visual scale infront of him on the table and after

tasting a sample is instructed to

physically place the sample on the

scale.

Limitation: one attribute can be

evaluated at a time


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Procedure:

1. Panelist inspect the entire set of

samples and places the mostintense at the top end of the

scale and the least intense at the

bottom.

2. Panelist purposely rate each

sample relative reference item.


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Ranking

-orderly the products from weakest

to strongest on the stated- user friendly

- easy to understand


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Criteria for scale utility:

1.Simple

2. Unbiased3. Relevant

4. Sensitivity to sample difference

6. Reliable

7. Allows for appropriate and

different statistical analysis


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Insight:

There are many methods or

scales can be used in

determining a good quality

product thru sensory yet the

right method or scale must bekeep in mind.

Scale can be use depend on

how we want to be reliable and

on the number of sample.


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Bibliography:

http://books.google.com.ph/books?id=yrLfrVgU6C

sC&printsec=frontcover&hl=fil#v=onepage&q&f=true

Accessed: January 14, 2013

Gatchalian, Miflora M and Grace D. Brannan

,2009: Sensory Quality Measurement:

Statistical Analysis of Human Responses:

Quality Partners Company, Quezon City,

Philippines
http://books.google.com.ph/books?id=yrLfrVgU6CsC&printsec=frontcover&hl=filhttp://books.google.com.ph/books?id=yrLfrVgU6CsC&printsec=frontcover&hl=filhttp://books.google.com.ph/books?id=yrLfrVgU6CsC&printsec=frontcover&hl=filhttp://books.google.com.ph/books?id=yrLfrVgU6CsC&printsec=frontcover&hl=filhttp://books.google.com.ph/books?id=yrLfrVgU6CsC&printsec=frontcover&hl=filhttp://books.google.com.ph/books?id=yrLfrVgU6CsC&printsec=frontcover&hl=fil


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