Senior Experimentation Consultant

Business Unit: Conversion - We’re CRO experts who help brands to optimize their digital ecosystems, websites, platforms, and customer experiences to drive real, measurable growth.

Team: Consultants

Reporting to: Director of Experimentation Strategy

Location: London UK- Hybrid

ABOUT GAIN is a creative-led, insight-driven company that blends data, tech and creativity. We believe the best ideas emerge where intelligence and creativity unite, where insight sparks imagination, and where innovation turns possibility into progress. We are explorers of new frontiers, shaping bold strategies that move people, brands, and businesses forward. Individually and together, our specialist teams provide the vision, data, and confidence brands and organisations need to make braver, more impactful decisions. Today as GAIN, we work as a united force, using data to fuel creativity, and technology to unlock new possibilities. As imagineers we don’t just embrace innovation – we engineer it, transforming information into action, and ideas into breakthroughs. This is where rebel thinking, smart technology, and data-driven creativity shape the future.

Through our five specialist teams: Creative Studio, Conversion, Customer Science, Experience and Performance. Individually, and together, we work to fuel your growth and deliver measurable impact.

THE ROLE As a Senior Experimentation Consultant, you will take ownership of the experimentation strategy and overall direction for your assigned accounts, ensuring programs are strategically aligned with client business objectives and deliver measurable impact. You will be responsible for setting and driving the big-picture experimentation approach, ensuring testing roadmaps, prioritization, and insights are effectively leveraged to support client growth. You will work closely with Project Managers and the broader delivery team to execute experimentation programs while collaborating with Principal Consultant to align on strategic direction and secure sign-off on key decisions. Beyond client delivery, you will mentor and upskill Consultants, support the Director of Experimentation and Principals in knowledge-sharing efforts, and contribute to the growth and development of the consultancy team. You will also play an active role in account performance and growth, contributing to discussions on profitability, performance, and identifying opportunities for expansion, while ensuring all strategic decisions are made in alignment with the Principal Consultant.

RESPONSIBILITIES

• Account experimentation strategy & execution: Drive & own the experimentation strategy for assigned client accounts, ensuring structured, data-driven approaches to testing and optimization while keeping the Principal informed and securing sign-off on key decisions.
• Leverage all relevant frameworks and tools within Conversion’s experimentation toolkit, selecting the right methodologies to drive performance for each client.
• Work closely with the delivery team to ensure experiments are executed efficiently, troubleshooting potential roadblocks and maintaining alignment on priorities.
• Oversee the development of research deliverables where experiments are not the immediate outcome, ensuring insights are clearly structured and presented to drive client decision-making.
• Conduct and facilitate bi-annual strategy reviews, ideation sessions, and other key workshops to ensure continued program maturity and alignment with business objectives.
• Ensure experimentation insights and research findings are communicated effectively, crafting compelling narratives that reinforce business value and influence client decision-making.

Client leadership & account growth

• Take ownership of the overall performance of assigned accounts, ensuring experimentation programs drive measurable impact and align with client business objectives.
• Contribute to uncovering the client’s bigger picture—gaining a deep understanding of their business objectives, challenges, and expectations beyond experimentation to ensure alignment with their broader goals.
• Lead strategic discussions on client objectives, challenges, and expectations for their experimentation program, ensuring we recommend the right solutions—whether experiments, research initiatives, or other evidence-based approaches.
• Identify and shape commercial opportunities within accounts, ensuring experimentation and research support client growth and long-term success.
• Act as a trusted advisor to clients, fostering strong relationships, driving program maturity, and positioning experimentation as a critical business function.
• Ensure alignment with the Principal Consultant on all strategic, big-picture, and commercial decisions.

Mentorship & team development

• Mentor and support Consultants, providing guidance on experimentation methodologies, strategic thinking, and client management to enhance their effectiveness.
• Facilitate structured knowledge-sharing initiatives, ensuring insights from client work are documented and leveraged for broader team learning.
• Support the Director of Experimentation and Principal Consultants in upskilling the team by delivering training sessions and fostering a culture of continuous development.
• Provide regular coaching and structured performance feedback, ensuring Consultants have clear development pathways and the support needed to progress in their roles.

Thought leadership & internal projects

• Develop deep expertise in Conversion (but not limited to) experimentation methodologies, ensuring mastery of frameworks, statistical principles, and strategic tools to drive high-impact testing programs.
• Drive innovation in experimentation methodologies, contributing to internal discussions on best practices and evolving strategies.
• Contribute to industry thought leadership, including blog content, case studies, or speaking engagements where relevant.
• Assist the Director of Consultancy and Sales team in pitches and business development efforts by providing strategic experimentation expertise.

5+ years of hands-on experience in experimentation / CRO / evidence-based optimisation, including designing and running A/B tests end-to-end. Strong agency or consulting experience, ideally managing multiple clients or complex experimentation programmes. Proven ability to leverage experimentation frameworks to drive strong, strategic, long-term experimentation programmes. Demonstrated experience setting strategic direction and shaping high-impact experimentation roadmaps. Strong stakeholder management skills, including experience working with senior/executive stakeholders. Demonstrated ability to coach and develop team members. Strong commercial awareness, with experience owning performance of a portfolio or major accounts. Excellent communication skills, translating data and insights into clear and persuasive narratives. Deep understanding of conversion principles, UX, analytics, user research, persuasion, and experimentation frameworks. Experience collaborating cross-functionally with delivery, analytics, design, and product teams.

HOW YOU’LL WORK

• Rebel Thinking: We don’t accept “good enough”. Rebel Thinking is about curiosity with courage. We make it safe to question assumptions, challenge the obvious, and explore smarter, braver ways forward, even when it feels uncomfortable. This is how new ideas, better products, and real breakthroughs happen.
• Make It Happen: “We turn intent into momentum.” Making it Happen is about turning ambition into action. We move fast, learn fast, and push through obstacles together. Progress beats perfection, and momentum creates impact.
• Swarming Our Expertise: “Individually smart. Collectively unstoppable.” Swarming our Expertise means we win together. We commit to developing our expertise so that by combining diverse skills, perspectives, and experiences, we solve harder problems faster and deliver results no single expert could achieve together.

Our benefits for UK employees include: Private Medical Insurance, Life Assurance, Income protection, Employee Assistance Programme, Cycle to Work salary sacrifice scheme, Tech & Wearables salary sacrifice scheme, Octopus EV Scheme, Discounts and deals on a range of items from hotels, holidays and hormone testing to cinema, gyms and will writing, GAIN Academy: our internal learning and development hub, a place to grow your skills, explore new ideas, and take your career in the direction you want.

GAIN is an equal opportunities employer and positively encourages applications from suitably qualified and eligible candidates regardless of sex, race, disability, age, sexual orientation, gender reassignment, religion or belief, marital status, or pregnancy and maternity.