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Fundamentals of Discrimination Testing

and Drivers of Liking®

May 23 - 25, 2023

The Royal Savoy Hotel & Spa | Lausanne, Switzerland


*Virtual and in-person attendance options are available for this course

This course has been developed for technical and supervisory personnel involved in all aspects of sensory and consumer research.



  • Printed manuals of slides and exercises

  • 3-month free software trial of IFPrograms® Professional 

  • A printed copy of our book, Tools and Applications of Sensory and Consumer Science and PDF downloads of the following 2 books: Thurstonian Models: Categorical Decision Making in the Presence of Noise

The instructors for this course will be:


The Institute for Perception


The Institute for Perception

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The Institute for Perception

Tuesday, May 23  |  8:30 - 16:30 CET


  • The broad range of Thurstonian models: Triads and tetrads, dual pair, m-AFC, triangle, duo-trio, same-different, degree of difference, ap-plicability scoring, first-last choice, maxdiff, just-about-right scales, category scales, and ranking

  • Response-based analysis vs. Thurstonian models

  • Thurstonian models for discrimination testing: Variability, decision rules, d' values and variances

  • Detailed account of common difference testing methods: 2-AFC, duo-trio, triangle, tetrad

  • A better alternative to proportion detectors in the population

  • Why the tetrad is superior to the triangle and duo-trio methods

  • Power and sample sizes for difference testing methods

  • Consumer-relevant action standards and how to create them

  • Same-different vs. paired preference for consumer relevance

  • Risk and sample size when switching to the tetrad method

  • Building a successful internal sensory program


IFPrograms® Exercises

  • Ingredient supplier change: Texture of cookies using 2-AFC and triangle

  • Consumer preference without a sensory difference

  • Variability in proportion detector estimates

  • Estimating panel sample sizes as a function of method, power, allpha, and size of the difference

  • Same-different method to establish consumer relevance (δR)

  • Linking internal panel and consumer sensitivities

  • Switching from the triangle to the tetrad method

  • Internal sensory program development at a major food company

Wednesday, May 24  |  8:30 - 16:30 CET


  • Why liking and utility are forms of similarity

  • Why link consumer and sensory data?

  • The sensory space in contrast to the Drivers of Liking space

  • How to plan a category appraisal (IFPrograms® exercises)

    • Product selection using graph theory

    • Method comparison to generate sample presentation orders

    • Multiple day effect, complete vs. incomplete block designs

  • First mapping option for ingredient change project

    • Factor analysis and its limitations

    • Assumptions and potential limitations of the approach

Thursday, May 25  |  8:30 - 16:30 CET


  • Introduction to Landscape Segmentation Analysis® (LSA): Liking as a form of similarity (IFPrograms® exercises)

    • Successive analytical steps

    • Unfolding—combining models from Thurstone and Coombs

  • Applications of LSA principles to ingredient change project (IFPrograms® exercises)

    • Creating the product and consumer ideal point space

    • Studying consumer segmentation

    • Regressing sensory and analytical information to uncover the driv-ers of liking

  • Limitations of internal and external preference mapping that do not account for perceptual variance and individual ideal points

  • Application of LSA to 27 real-world category appraisals

  • Using the Drivers of Liking Space (IFPrograms® exercises)

    • Creating optimal product sensory profiles and portfolios

      • Maximizing consumer satisfaction (absence of competition)

      • Best strategy to avoid cannibalization

      • Maximizing first choice against competition

      • Using machine learning to characterize uncovered consumer subgroups

  • Extending the use of an LSA space: New product predicted perfor-mance (IFPrograms® exercises)

    • Determine the spatial location of new products using their sensory and analytical profiles

    • LSA as a computer-aided design tool: Predict consumer acceptability using ideal points without new consumer testing

  • Novel applications of LSA in the real world

  • Course conclusions


Please enter your information below to register for this course. Those registering 2 or more attendees from the same company are eligible for a 10% discount on the 2nd registration. Please contact us before registering if you are eligible for a discounted rate. 

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