• Effet Majeur

    Strategic consulting for critical decisions.

    Since 2009, our experts in Psychology, Sociology, Economics & Innovation Strategy have been advising those who need to identify the decisive effects to act:

    We defended French cultural exception (Deezer). We upended the rules of traditional hospitality (AccorHotel Jo&Joe). We got young people into sports (UCPA SportStation). We helped recycle french luxury (Dior) and brought it to the world stage (Chanel). We kept people from ending up in debt after a holiday accident (Allianz). We fueled young people's passion for home design (IKEA). We helped farmers irrigate without water loss (Telaqua). We defended the French internet (AFNIC) and domestic SMBs (EulerHermes). We helped advance women's health (Organon)...

  • Strategic consulting to decide under uncertainty

  • We are featured in the national press

    Harvard Business Review, Challenges, le Figaro, 20mn talk about our achievements

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    AccorHotels Jo&Joe

    Read the Harvard Business Review, Challenges and Le Figaro article on how we helped Marie-Suzanne Locqueneux think about the service strategy of the new AccorHotels brand

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    UCPA Sport Station

    The interview on the construction of the new UCPA sports complexes which aim to bring sport and health back into your daily life

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    Epitech Digital

    The article in the newspaper 20 mn where we talk about our students and how we teach them to respect users who can never be reduced to simple consumers

  • The Opinions of our corporate customers

    All our reviews are verified by Sortlist 

    Allianz, personal & travel insurance

    User Research & Strategic Design for the group's innovation projects

    "Effet Majeur has been working on our innovation projects for almost 5 years now.

    We appreciate the quality and relevance of their work and the deliverables, which always meet our expectations perfectly. In particular, the quality and depth of the strategic analyses.

    Deezer, musical streaming

    User Research & Strategic Design to manage the shift from family customers to Generation Z customers

    "We appreciated not only the quality of the research carried out, but also the professionalism of the team and their willingness to talk to us throughout the study".

    Organon, women health laboratory

    User Research & Strategic Design to meet the demands of the new generation of doctors in terms of laboratory advice

    "Effet Majeur has very strong expertise in both user research and strategy and they don't count the hours in producing quality deliverables."

    Euler Hermes, crédit insurer

    User Research & Strategic Design to find a fit to market with SME customers

    "Olivier's support, in particular his ability to analyse and his vigilance in not falling back into the ways of business experts / keeping the chakras open".

    Rhomberg, Swiss Jeweller

    User Research & Strategic Design to continue the brand's internationalisation and connection with French customers

    "The Effet Majeur agency was always ready to help us and was able to meet our deadlines thanks to a well-structured project. The mock-ups provided fully met our expectations, thanks in particular to user testing. An agency to be recommended."

    En Voiture Simone, auto-écoles en lignes

    User Research & Strategic Design to better meet the needs of Generation Z

    "We really liked Effet Majeur's professionalism: on time, on schedule, impeccable project management, and the quality of the deliverables."

    UCPA Sport Station

    User Research & Strategic Design of new sports complexes in delegation

    "We really appreciated the uniqueness of the work methodology based on human sciences and design. The relevance and approach of the agency's founder".

    Perial investissements SCPI

    User Research & Strategic Design to transform brick-and-mortar property into a relevant investment option for Generation Z

    "The team's active listening and ability to take us down a path never taken by our market, while remaining true to our values."

  • OUR METHOD TO IDENTIFY THE DECISIVE EFFECT

    1

    Psychology

    To diagnose what's really blocking progress — the invisible power dynamics, the unspoken resistance, the deep mechanisms preventing action.

    2

    Strategy

    To move beyond superficial and cosmetic solutions, reframe the stakes at their root, identify the decisive effect that will tip the situation.

    3

    Simulation

    To test your options before committing, anticipate reactions, validate that your plan will hold against reality. You don't decide blindly.

  • DIAGNOSe WHAT'S REALLY BLOCKING PROGRESS

    You're facing resistance you don't understand. Your project stalls despite all efforts deployed. Users don't engage. Stakeholders drag their feet for no apparent reason. The problem is never the one they present to you.

    Classic diagnostics (surveys, focus groups, superficial interviews) only capture surface-level discourse. What people say is never what makes them act. It's time to call on experts — Psychologists and Sociologists — capable of revealing invisible power dynamics, unspoken resistance, the deep mechanisms that paralyze action, the work of the negative.

    We use proven methods: projective tests to understand what people cannot express, what is not explicit; usage mapping tests to trace the complexity of situations and tasks; literature reviews to capitalize on all scientific knowledge; scientific experiments to identify the causes of the situations and distinguish truth from falsehood; constraint tests to grasp the dynamics of trade-offs; iconic tests to understand how graphic dimensions and communication affect decisions...

    But above all: psychological modeling of change levers — identifying who influences whom, what fears block, what desires are at work and must be supported.

    Usage Mapping tests

    Iconic Tests

    Constraints Tests

    Scientific Experimentations

  • International user research

    Through the projects carried out for our major customers, we have built up a network of partners capable of carrying out user tests all over the world. We cover key countries such as France, England, Germany, Spain, Italy, Scandinavia, the United States, Australia, Singapore and Dubai. If your project has an international stature, we can help you.

    Paris, Londres, Francfort, Madrid, Rome

    Test rooms, User Research, User tests

    Dubai, Ryad, le Caire

    Test rooms, User Research, User tests

    Sydney

    Test rooms, User Research, User tests

    Mexico, Rio, Sao Paulo

    Test rooms, User Research, User tests

  • A breakthrough strategy, the real thing

    You are a decision-maker — CEO, Managing Director, political leader, founder. You can no longer settle for superficial analyses and generic recommendations. It is your responsibility to deeply understand the stakes and decide with clarity.

    We have supported Allianz, AccorHotels, UCPA, Chanel... to rebuild their strategic approach. Our expertise: psychological modeling (identifying change levers), behavioral economics (understanding real trade-offs), economic model (validating viability), game theory (anticipating adversarial reactions), decision theory (deciding under uncertainty), risk theory (assessing what can tip), applied military strategy (defining the decisive effect and simulating your options).

    The worst that can happen is to invest months in analysis and watch all your efforts collapse at the moment of execution. We help you preserve coherence between diagnosis, modeling, and action.

    Don't launch projects without knowing where you're going.

    Strategy

    Business Model & Game Theory

    Tactics

    Decision Theory & Risk Theory

    Engagement Mechanics

    Psychological Modeling & Behavioral Economics

    Design Sprints

    Prototyping, Simulations & Game Design

  • STATISTICS TO VALIDATE YOUR HYPOTHESES

    First, define the right indicators. When you understand how mechanisms work through psychological modeling, you can build strategic KPIs that truly measure what matters: your project's viability, real impact, operational effectiveness — not just conversion numbers.

    Then, validate your hypotheses with rigorous statistics. You need to know if your diagnosis holds against the facts, if your options are viable, if your levers will work. Our statisticians in Human Sciences graduated from ENSAE (INSEE) and master advanced methods — qualitative and quantitative, parametric and non-parametric.

    Finally, choose the right test to decide. Move beyond basic descriptive statistics that mislead you. We use: causality tests (regression, ANOVA), predictive statistics (Bayesian models, machine learning), factor analysis (PCA, CA) to reveal hidden structures, structural equation models (SEMs) to test your strategic hypotheses, segmentation analysis(clusters, typology), non-parametric tests (binomial, Chi-square goodness-of-fit, Kolmogorov-Smirnov, McNemar, Chi-square association, Spearman, Wilcoxon, Fisher exact, Cramér...). We identify critical variables, detect weak signals, validate your decisions on scientific data — not intuition.

    Descriptive Statistics

    Mean, Median, Standard Deviations...

    Inferential Statistics

    Parametric & Non-parametric

    Correlation Tests & Effect Size Tests

    Spearman, Cramer...

    Marketing Tests

    CA, PCA, Clusters...

  • Our Digital & Retail Expertise

    Understand your users

    Literature reviews
    Online surveys, Barometers, Customer listening
    User Research
    Psychology / Sociology of uses
    Projective tests & Analysis of the unspoken
    Foresight
    Emerging trends & Weak signals
    Scientific experiments
    International studies
    Test logistics (panels, recruitment...)

    Launch new concepts

    Literature reviews
    Online surveys, BarNeeds & Expectations studies / Market research
    Exploration of new market segments
    Exploration of new product lines
    Detection of competitors' opportunities & weaknesses
    Narrative construction
    Testing commercial & communication offers
    New service design
    Mockups / Prototypingometers, Customer listening
    User Research
    Psychology / Sociology of uses
    Projective tests & Analysis of the unspoken
    Foresight
    Emerging trends & Weak signals
    Scientific experiments
    International studies
    Test logistics (panels, recruitment...)

    Inventing new services & Innovating

    Statistical data analysis (Online surveys & Data)
    Research & Understanding user needs
    Market usage diagnosis
    Innovation strategy building
    Axiomatics & Disruption axes
    Engagement design
    Ethical & equitable design possibilities
    Mockups & Prototyping
    Concept testing

    Strategic realignment

    User needs modeling
    Search for disruption axes
    Users' real trade-offs
    Competitive analysis & Strategic watch
    Anticipation of competitors' trade-offs
    Economic model & Viability analysis

    Support for decision unblocking
    Strategic scenario simulation
    Success / failure KPI definition
    Predictive models
    Statistical validation of concepts
    Tracking decisive effects

    Prototyping & Simulations

    Ergonomic audits / Existing audit
    Design sprint
    User personas
    User journeys
    Engagement mechanics
    Service tree structure
    Ergonomics & UX
    Macro-architecture & Wireframes
    Graphic design & Art Direction
    User testing

    Against Nudging & Neuromarketing

    Place & Importance of humans in innovation logic
    Search for bright patterns for users
    Innovation through Human Sciences
    Effectiveness of ethical practices
    Psychology & Customer listening
    User Research & UX Design

    Training with Les Gobelins
    Training with IONIS Education Group
    Incubators