Triangle

Triangle

Introduction

The triangle method is used to understand the presence or absence of a perceptible sensory difference or similarity between samples of two products through a forced-choice approach. Participants are presented with three samples, two of which are the same. The task of the panellists is to identify the odd sample in the group. 
The method is applicable to scenarios where a difference may exist in a single sensory attribute or across multiple attributes. It is considered to have more statistically efficient compared to the duo-trio test but is less suitable for products with pronounced carryover and/or lingering flavors. The method is adaptable even when the specific nature of the difference is unknown, meaning it does not determine the size, direction, or attributes responsible for the difference.

Template Description

The template starts with a screen, which can be used for welcoming panellists or asking additional questions prior to the triangle test. In the design section, the first screen has instructions specific to the triangle task, followed by a question where participants are presented with three blinded-coded samples and are asked to indicate which is the odd sample of the three. Once the task is completed, panelists have the opportunity to add comments. This option can be utilized if panelists wish to provide reasoning for their choice.
On the end screen, the template incorporates a thank-you message, providing an opportunity for you to personalize a final message for the panellists. 
Within the design settings, you can examine how each panellist will receive the sample, with each set corresponding to a specific order of presentation for an individual panellist. The test employs a block design, presenting three samples simultaneously to the panelists. The order of presentation is randomized across all sets/panellists. 

In EyeQuestion, you have the option to select the Triangle Feedback Template. This template provides panelists with feedback on their task on the end screen, informing them whether they have correctly identified the odd sample. This feature can be particularly valuable during training.
After the triangle task in the design section, six additional questions are incorporated into this screen. The text questions called “Order Block” are included to show panellists on the screen the samples that were provided, while the other questions included are formula questions. These formula questions allow for result calculations, which are then displayed to panelists in the end screen. The formulas indicate that if panelists answer incorrectly, they will see the word "Wrong," and if they answer correctly, they will see the word "Correct". The calculation is repeated three times, as this template includes the option to repeat the same triangle test three times. In the end screen, a table with a placeholder shows the answer from the formula and the order question type to the panelist. It is important not to change the names of the question types in this template to ensure that the feedback functions accurately.

Raw Data Representation

The raw data will be displayed, with each row corresponding to an individual judge and the pair of products they were presented with. The data will be stored to indicate whether the panellists correctly placed the identical samples within the same group or not. If the answer is incorrect, the data will be recorded as a 0, whereas if the panellists answer correctly, the data will be recorded as a 1. The Q1_info column provides additional information about the order of samples provided to the panellists and the answer selected.
The Triangle Feedback Template results export displays a separate row for each repeated triangle task. Furthermore, in the raw data, the results from the formula and the order question type are also presented.

Analysis

Once data has been gathered, you can access EyeOpenR and navigate to the Discrimination methods. Choose the analysis “Triangle” to examine your results. Additional details about this analysis can be found in the following article:

References

  1. ISO 4120:2004

    • Related Articles

    • How to Display Feedback of Triangle and Tetrad Test

      Introduction During a Triangle test a panellist is presented with three samples of which two are equal and one is different. A panellist must point out the odd sample. A user can add the screen condition in the triangle test to display message when a ...

    • Tetrad

      Introduction The Tetrad method is a testing procedure designed to understand the presence of a perceptible sensory distinction between two products. Panelists are given four samples, with two being identical and two being different. The panellists ...

    • Three-Alternative Forced Choice (3-AFC)

      Introduction The three-alternative forced choice (3-AFC) method is a discrimination method where panelists are presented with three samples simultaneously and instructed to identify the sample(s) that are higher or lower in a specified sensory ...

    • Paired Comparison

      Introduction The paired comparison method is a handy method to use when dealing with products that have a lasting effect or are in short supply. Unlike other tests like the triangle or duo-trio, it works well when showing three samples at once isn't ...

    • Two-Alternative Forced Choice (2-AFC)

      Introduction The Two-Alternative Forced Choice (2-AFC) method, is a specific way of comparing two samples in sensory science. In this method, the only allowed difference between the two samples is a specified sensory characteristic. It works well ...