Principal Effectiveness Consultant

MediaLab Group; City of Westminster; Hybrid; GBP 60,000 - 80,000; Full time

Job summary

A leading media agency in the UK seeks a Marketing Effectiveness expert to lead projects that help clients understand the value of their media investments. The role involves leading Marketing Mix Modelling projects, consulting with clients, and mentoring team members. Ideal candidates will have 6-7+ years in media measurement and strong problem-solving skills, contributing to actionable insights and business growth strategies. The position offers a competitive salary and various employee perks including hybrid working and health benefits.

Benefits

Competitive salary package

Hybrid Working

Health & Wellbeing benefits

Qualifications

• 6-7+ years’ experience in media measurement & effectiveness.
• Strong consulting and problem-solving skills.
• Ability to translate measurement frameworks into business growth strategies.

Responsibilities

• Lead end-to-end Marketing Mix Modelling (MMM) projects.
• Act as a consultant for client measurement frameworks.
• Develop client presentation materials and communicate insights.

Skills

Experience in media measurement & effectiveness

Marketing Mix Modelling (MMM) expertise

Consulting and problem-solving skills

Statistical analysis

Strong project management skills

Tools

SQL

GCP

R/Python

Job description

JOIN OUR JOURNEY

Medialab is the UK’s leading independent media agency, and one of the fastest growing in the industry. We’re a media agency that’s made differently: purpose‑led, data‑driven, founder‑run and proudly independent.

Our entrepreneurial spirit means success is recognised and rewarded. There are no limits to what you can achieve here, which our employees agree with, evidenced by being a Campaign Best Place to Work for six consecutive years and one of The Sunday Times Best Places to Work 2025. As well as this, we’re Campaign’s Independent Agency of the Year 2024 and Media Week’s Independent Agency of the Year 2025.

We are IPA Effectiveness accredited, an IPA People‑First agency, and All in Champions, with industry‑leading work recognised by double‑gold at the 2024 IPA Effectiveness Awards for our work with Laithwaites and a 2025 Effie for our work with Alzheimer’s Society.

Our independence means we can focus 100% on doing the right thing to secure success for our clients and our brilliant people. We work with a wide variety of clients including Hovis, IG, Sharps Bedrooms, SunLife, Standard Life, Ancestry, Laithwaites Wine, Save the Children, Guide Dogs, Alzheimer’s Society, RNLI and Clearscore.

OUR VALUES

• Commit to Doing the Right Thing (Act with integrity and accountability)
• Help People Flourish (Invest in people)
• Dig Deeper to Understand Better (Data driven curiosity)

OUR COMMITMENT TO YOU

Working at Medialab comes with lots of perks including all the usual things you would expect, such as a competitive salary package, pension, season ticket loans, cycle to work scheme, weekly social events and big summer / end of year parties.

On top of that, we offer extra benefits, which make life at Medialab even more rewarding:

• Time to Unwind – 25 days holiday (+ Christmas holiday closure), a day off for your birthday, holiday buying scheme, flexi‑hours and work abroad scheme.
• Hybrid Working – Balance between home and office. We welcome requests for flexible working arrangements from the commencement of employment.
• Career Growth – A meritocratic approach to progression with quarterly reviews, CPD Platinum accredited training, mentoring and leadership support.
• Health & Wellbeing – Private medical insurance, health cash plan, gym discounts, wellbeing apps Mental Health First Aiders and free professional counselling.
• Supporting Families – Enhanced parental leave pay, flexible working and life assurance.
• Giving Back – Paid charity days and sustainability initiatives.
• Perks & Rewards – Retail discounts, long‑service trips and an unforgettable team culture.

YOUR NEXT CHALLENGE

This role sits within the Marketing Effectiveness team at Medialab, helping clients understand the true value of their media investments through advanced measurement solutions, statistical modelling, and integrated insights, which evolve into live & automated reporting solutions.

Reporting to the Head of Marketing Effectiveness, you will lead modelling workstreams, ensure quality control, and integrate research from multiple sources to deliver actionable insights that make a difference to client outcomes.

You will play a dual role: supporting and mentoring team members while continuing to develop your own skills alongside industry experts. Our proprietary Apollo platform automates data collection, allowing the modelling team to focus on insight generation and strategic recommendations rather than manual data processing.

HOW YOU WILL MAKE AN IMPACT

• Lead end-to-end Marketing Mix Modelling (MMM) projects, from model development to insights generation and data storytelling.
• Act as a consultant, working with client teams and client partners directly to ensure measurement frameworks align with their business challenges.
• Serve as the key point of contact for a diverse client set, developing sector expertise.
• Develop client presentation materials and communicate complex insights in a clear, actionable way.
• Identify new business opportunities, contribute to pitches, write proposals, and create thought leadership pieces.
• Drive innovation in automated modelling processes, collaborating with engineering teams to enhance efficiency.
• Represent Medialab externally, building strong relationships with clients and industry stakeholders.

WHAT YOU BRING TO THE TEAM

Must Have Skills

• 6-7+ years’ experience in media measurement & effectiveness, with hands‑on Marketing Mix Modelling (MMM)/econometrics expertise.
• Strong consulting and problem‑solving skills, with the ability to translate measurement frameworks into business growth strategies.
• Experience in managing and mentoring other consultants/data scientists.
• Solid understanding of advertising and media planning, working closely with planners and buyers.
• Proven track record in statistical analysis, with the ability to interpret large datasets using various tools.
• Strong project management skills, overseeing the end‑to‑end delivery of modelling projects.
• Passion for media, marketing, and emerging measurement challenges.

Nice to Have Skills

• Ability to interpret client needs and apply commercially relevant analytical solutions.
• Excellent communication skills, with the ability to simplify complex data for all levels of an organization.
• Curiosity and innovation, exploring new approaches and data sources to improve insights.
• Comfortable working with SQL, GCP, R/Python, or visualisation tools.
• Experience with model automation and system integration is a plus.
• Familiarity with the charity and financial services sectors is beneficial.