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| DISCRIMINATION PAIRED COMPARISON EXAMPLES
PC Forced and Non-Forced |
Discrimination Paired Comparisons Incomplete Block Paired Comparisons View More Question Type Choices |
Notes:
*** Discrimination Attributes ***
-------------------------------------
Use Discrimination questions to test for the perception
of small differences in sample stimuli.
Triangle
========
Panelist is presented with three coded samples, two of which are identical.
The panelist is asked to pick the sample which is different from the others.
Example: Please evaluate all three samples, in order from left to right,
then select the one sample which is different from the other two.
Result Data Values for Discrimination Triangle Tests: 1=Correct 0=Incorrect
Duo-Trio (Rotated or Constant)
==============================
Panelist is presented with two coded samples and an identified reference sample.
One of the coded samples will be identical to the reference sample.
The panelist is asked to choose which of the two coded samples is different
from (or identical to) the reference sample.
There are two types of Duo-Trio sample presentations:
Rotated - the reference sample is ROTATED between the the two test samples.
Constant - the reference sample is always CONSTANT as the control sample.
Example: Please evaluate the samples in order from left to right,
then select the sample which is the same as REF.
Result Data Values for Discrimination Duo-Trio Tests: 1=Correct 0=Incorrect
Paired Comparison
=================
Panelist is asked to compare two samples on the basis of some specifically
defined criterion. There are two types:
Forced - The panelist must select one of the two samples. (PC)
Not Forced - The panelist can select 'Neither' to mean both samples are the same. (PCN)
Optional: See Choices Tab to select custom text for No Preference.
Example: Please select the sample that is sweeter.
Result Data Response Values for Discrimination Tests (PC, PCF)
Is the Absolute Sample Number SELECTED by the panelist:
Paired Comparison Data value '1' means Panelist selected Absolute Sample 1
Paired Comparison Data value '0' means Panelist selected Absolute Sample 2
If PCN & No Preference selected, response value is Null '.'
Slightly different on Test Data Results Report, 1 = Sample1 & 2 = Sample2
Paired Comparison Reports:
- See Statistics areas, Discrimination Binomial Analysis.
- See Reports dropdown menu, Discrimination Reports, Paired Comparison Attribute Analysis.
- See Reports dropdown menu, Raw Data Exporting.
- And other reports.
2-AFC (Alternative Forced Choice) is also known as a Paired Comparison Test.
- Use this method to test for sensory differences between two samples, such as 'which sample is sweeter'.
- set up your 2-AFC as a Paired Comparison test, with PC or PCN, where an answer is forced or not forced.
- Same SIMS 2000 Paired Comparison Attribute Analysis, in addition to the other available reports.
- Reference #1: Sensory Evaluation Techniques, Civille, 3rd Ed.(pg 100), 2nd Ed.(pg 100).
Incomplete Block Paired Comparisons
Also commonly referred to as multiple paired comparision, multiple paired preference, pairwise ranking, and incomplete block paired preference.
Can not use the typical Discrimination PC since a 2 sample, complete block design is required.
Incomplete blocking such as 3C2, 4C2, 5C2, etc., when Samples >=3, and presenting only two samples.
Recommendations:
1) Ranking; Paired Comparison is similar to Pairwise Ranking.
Use an Affective type Questionnaire, SIMS 2000 Ranking Attribute question, 'rank all'.
2) Hedonic; using SIMS 2000 hedonic attribute type, 'select one'.
Set up the ballot as an Affective questionnaire using Hedonic Attributes instead of the typical two sample Discrimination PC.
Affective questionnaire will allow for more flexible Incomplete Block Experimental Design and Experimental Plan Rotations.
Create an Hedonic attribute type with two choices and label the choices them with the following special TAGs.
<RELATIVE_SAMPLE_1_BLINDING_CODE> select the choice return value to be = 1
<RELATIVE_SAMPLE_2_BLINDING_CODE> select the choice return value to be = 2
The above example will present two choices with the blinding codes for the two samples in randomized order perfectly matching the Rotation Plan in the Test Definition.
Example: Which Sample do you prefer OVERALL?
( ) 135 ( ) 246
Note: The 'Attribute Seen With:' option should be set to 'Relative Sample -- Last Sample', so that this question is only seen once at the end of the ballot.
Note: See Webpage: http://www.SIMS2000.com/Sample11.asp for additional and the latest information.
Positioning of Discrimination Attributes in Affective Questionnaires
====================================================================
There are several rules to follow when including a Discrimination
Attribute in an Affective Questionnaire:
1. The Discrimination Attribute must be either 'Seen With Sample Order 1'
or 'Seen With Sample Order 2.'
2. If a Discrimination Attribute is Seen With Sample Order n, then
all discrimination attributes in the same questionnaire must also
be Seen With Sample Order n, where n = 1 or n = 2.
3. All attributes seen on the same page as a Discrimination Attribute
must be seen with same sample as the Discrimination Attribute.
4. You can include any attribute type except 'Time Intensity' on the
same page as a Discrimination Attribute.
Same/Different Tests in SIMS 2000 Chi-Square Analysis
========================================================
The Same/Different Test is also commonly referred to as the Simple Difference
Test. The Same/Different Test method is sometimes used when your two samples
are unsuitable for triple or multiple test presentations, e.g. when the
Triangle and Duo-trio tests can not be used.
Although SIMS 2000 does not have a specifically named Same/Different
Test option, it is fairly easy to set up.
On its web site Sensory Computer Systems has posted an EXCEL file which
describes how to set up a Same/Different Test in SIMS 2000.
Website Forum Link: http://www.sensorycomputersystems.com/phpbb2/viewtopic.php?t=60
The Excel File is organized in three simple worksheet tabs.
1. TestPreparationNotes, how to quickly setup the test in SIMS 2000.
2. SIMSTestData, how to get your Same/Different data to Excel.
3. Chi-SquareAnalysis, the statistics.
The Excel File is located in the online forum area at www.SIMS2000.com,
Click on Support, Forums, and Search for 'Same' and 'Difference'
It's easy.
Time needed to setup test in SIMS 2000 = 5 minutes.
Time needed to export data into Excel Spreadsheet = 3 minutes.
Time needed to get to final Chi-Square statistics = 1 minute.
A - Not A Tests in SIMS 2000 Chi-Square Analysis
========================================================
The A - Not A Test method is used to determine whether a sensory difference
exists between two products. It is sometimes used when your two samples are
unsuitable for triple or multiple test presentations, e.g. when the Triangle
and Duo-trio tests can not be used.
Although SIMS 2000 does not have a specifically named A - Not A
Test option, it is fairly easy to set up.
On its web site Sensory Computer Systems has posted an EXCEL file which
describes how to set up a A - Not A Test in SIMS 2000.
The Excel File is organized in two simple worksheet tabs.
1. TestPreparationNotes, how to quickly setup the test in SIMS 2000.
2. Chi-SquareAnalysis, the statistics.
The Excel File is located in the online forum area at www.SIMS2000.com.
Click on Support, Forums, and Search for 'Chi-Square'
It's easy.
Time needed to setup test in SIMS 2000 = 5 minutes.
Time needed to export data into Excel Spreadsheet = 3 minutes.
Time needed to get to final Chi-Square statistics = 1 minute.
Difference-From-Control Test
============================
Use this test when the project objectives include the following:
O Determine whether there is a difference between a control (reference) sample
and one or more other samples.
O Estimate the degree of such difference(s).
Although SIMS 2000 does not have a specifically named Difference-From-Control test,
it is fairly easy to set up.
On its web site Sensory Computer Systems has posted a detailed forum document on how to
set up this type of test. It is located at http://www.SIMS2000.com.
Click on Support, then Forums. Search for 'Difference' and 'Control.'
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