Data Scientist, Marketing Mix Modelling

s360 A/S; Barcelona; On-site; EUR 65,000 - 90,000; Full time

Job summary

s360 seeks a Data Scientist based in Barcelona to lead Marketing Mix Modelling engagements from data questions to client-ready recommendations. You will work with Meridian, PyMC-Marketing and Robyn, applying Bayesian modelling and robust diagnostics to deliver actionable insights for senior stakeholders.

You will collaborate with Digital Growth, account teams and measurement specialists, managing data intake, priors, and priors selection while communicating uncertainty clearly to clients.

Qualifications

• Experience with Marketing Mix Modelling delivery end-to-end.
• Ability to translate model outputs into client-ready recommendations.
• Comfort in presenting to senior stakeholders in marketing and finance.
• Strong data validation and diagnostics to ensure model trust.

Responsibilities

• Own Meridian MMM delivery from data questions to client-ready recommendations.
• Collaborate with clients, growth teams, and measurement specialists to ensure sound results.
• Conduct calibration and validation tests, including holdout and incrementality checks.
• Turn ROI and budget optimisation insights into clear client guidance.
• Manage data intake and modelling workflows in cloud environments and notebooks.
• Scope proposals and model refreshes with leadership for client engagements.

Skills

Bayesian MMM

Client delivery

Diagnostics & judgment

Media understanding

Client communication

Cross-disciplinary collaboration

Tools

Meridian

PyMC-Marketing

Robyn

Google Cloud

AWS

Azure

Colab

Python

Job description

Do you want to build models that shape how ambitious brands invest in marketing? Are you motivated by combining Bayesian modelling, commercial understanding, and clear client advice?

At s360, you will own Marketing Mix Modelling engagements from the first data questions through to client-ready recommendations. Based in Barcelona and working with clients across the Nordics and the UK, you will help turn Meridian models into decisions clients can act on.

Build models clients can trust

As our Data Scientist you will take ownership of Marketing Mix Modelling delivery from end to end. You'll work closely with clients, Digital Growth colleagues, account teams and measurement specialists to make sure every model is technically sound, commercially relevant and easy to understand. You will bring the business context into the model, raise issues early when a result looks off, and help the team deliver work that clients can trust and use.

Your main responsibilities will be:

• Model ownership: Build and sign off Meridian models end to end, covering KPI definition, geo-level design, prior selection, sampler settings, convergence and fit diagnostics.

• Client collaboration: Agree on data, priors, assumptions and expectations with clients before each build, then present the findings to senior marketing and finance stakeholders.

• Calibration and validation: Test model outputs against geo and holdout incrementality tests, and bring structured evaluation to results.

• Budget recommendations: Turn ROI, response curves, saturation and budget optimisation into clear recommendations clients can act on.

• Data and workflows: Manage data intake and validation with client teams, and run modelling workflows in Google Cloud / AWS / Microsoft Azure and Python Notebooks, e.g. Colab.

• Scoping and refreshes: Scope proposals and model refreshes for client engagements together with the Group Head of Measurement.

Join our international Measurement team

You will join s360's Measurement department as the go-to person for Marketing Mix Modelling, both with clients and inside s360. Most of your colleagues in Measurement build the tracking and data foundations that good models rely on, such as GA4, server-side setups and data quality. Your work starts after that: you decide how we build and calibrate our models, and you are the voice clients hear when we explain what the results mean. You will have real influence on how MMM grows with s360, including how incrementality testing fits alongside it. You will also work closely with Google's Meridian team on many of our existing engagements.

Your day-to-day base will be our office at Norrsken House Barcelona, which you'll share with colleagues from several s360 teams.

Bring Bayesian modelling and clear judgment

We're looking for a Data Scientist with technical depth, commercial curiosity and the ability to make complex things simple. You're comfortable owning the full modelling process, you ask the hard questions about data and assumptions, and you explain uncertainty in plain language.

You’ll probably be a good fit if you recognise the following about yourself:

• Bayesian framework expertise: Hands-on experience with Bayesian Marketing Mix Modelling in Meridian, PyMC-Marketing or Robyn, including adstock, saturation and prior selection.

• Client-ready delivery: The ability to deliver Meridian models that hold up in front of the client without rework, with well-founded priors, clean diagnostics and a clear readout.

• Model diagnostics and judgment: Experience with convergence, posterior predictive checks and fit, plus the judgment to tell whether a result is plausible.

• Media understanding: A solid grasp of how media is bought and measured across search, social, TV and offline channels.

• Client communication: Confidence in leading client conversations and explaining ROI, response curves and uncertainty in plain English.

• Cross-disciplinary collaboration: A collaborative mindset and motivation to work closely with colleagues across disciplines and markets.

What it's like working at s360

At s360, you will be part of a Marketing and AI consultancy, working alongside more than 330 skilled colleagues across 10 offices in 8 countries. While our shared mission is to help brands and retailers grow, we are equally committed to fostering a strong culture, defined by collaboration, drive, and continuous development. We believe that our culture and ways of working are key to delivering long-term, meaningful results.

As a part of our team, you can look forward to:

• Skilled colleagues: Collaborate with some of the brightest minds in the industry and be part of an ambitious team with deep expertise across all key digital disciplines.

• Top-tier clients: Work with some of the biggest brands in the world on solving their most complex and interesting commercial problems.

• Growth journey: Join one of the fastest-growing marketing and AI consultancies in Europe with the ambition of becoming the best in the world.

• International environment: With 10 offices across 8 countries, you will have the opportunity to collaborate with people from diverse cultures around the world.

• Career acceleration: Get individual career plans to influence your own professional path and contribute to shaping the company's future.

• Continuous development: A learning culture where people strive to become 1% better every day, supported by advanced training and knowledge sharing.