Principal Experimentation Consultant

Welcome to Gain Conversion! 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 organizations need to make braver, more impactful decisions.

At Conversion, we’re a team of global CRO experts who help brands optimise their digital ecosystems, websites, platforms, and customer experiences to drive real, measurable growth. We intend to prove that evidence-based decisions get the best results, and our people and unique culture are the fuel. As a certified Great Place to Work®, we support each other fully, without ego or drama, and stay focused on what’s best for our clients and each other. We’re proud to be an inclusive company where people can bring their whole selves to work. Our guiding principles - Be One, Be Decisive, Be Hungry, Be Undeniable, and Be Accountable - are at the core of everything we do. Here, you’ll work with talented, passionate people who challenge you to do your best every day.

The Role

As a Principal Experimentation Consultant, you will lead a portfolio of client accounts, driving high-impact experimentation strategies, ensuring commercial growth, and owning senior-level stakeholder relationships. You’ll set the strategic direction for your accounts, guide clients in making confident evidence-based decisions, and ensure that experimentation delivers clear business results. Internally, you’ll mentor and develop Senior Consultants and Consultants within your portfolio, uphold methodological excellence, and work closely with delivery leads to maintain consistent portfolio performance. You’ll also contribute to the evolution of our methodologies, support pitches and new business, and play an active role in shaping the future of the consultancy function.

Responsibilities

• Portfolio strategic leadership
  • Own and drive the strategic direction of client accounts, ensuring long-term program maturity and measurable impact.
  • Define and pursue the experimentation vision within your portfolio, ensuring alignment with broader business objectives.
  • Ensure frameworks in the Conversion toolkit are used consistently and effectively.
  • Act as a trusted strategic advisor to senior client stakeholders, translating experimentation insights into broader commercial strategy.
  • Partner closely with the Senior Project Manager to ensure seamless delivery and operational excellence.
  • Communicate experimentation insights clearly and persuasively to stakeholders.
  • Maintain a strong understanding of conversion drivers across UX, analytics, research, persuasion principles, and business context.
• Commercial & account leadership
  • Own the commercial success of your portfolio, including renewals, upsells, and long-term retention.
  • Lead revenue growth and renewal planning; identify expansion opportunities; ensure account stability.
  • Support and guide the team in identifying and closing commercial opportunities.
  • Represent Conversion in senior-level client engagements, building strong and trusted relationships.
  • Act as final decision-maker for key account-level decisions.
  • Proactively monitor satisfaction, identify risks, and implement mitigation strategies.
  • Step into accounts during critical phases (onboarding, transition) and hand off when appropriate.
• Mentorship, line management & team development
  • Coach and mentor Senior Consultants and Consultants on both technical and commercial skills.
  • Understand team strengths and development areas to support continuous growth.
  • Increase Consultant ownership of accounts based on readiness, while maintaining oversight.
  • Provide structured feedback and ensure high performance within the portfolio.
  • Flag training or support needs to leadership when required.
  • Foster an environment where team members collaborate effectively and professionally.
  • Make informed promotion recommendations based on impact and readiness.
• Thought leadership & internal projects
  • Contribute to the evolution of our experimentation methodologies.
  • Provide subject-matter expertise for thought leadership (blogs, case studies, speaking).
  • Support internal knowledge-sharing and cross-portfolio insight exchange.
  • Contribute to new product/service development to keep our offering competitive.
  • Collaborate with product and delivery teams to enhance efficiency and scalability.
  • Actively participate in team days, including running sessions.
  • Support hiring efforts when needed (screening, interviews, evaluation).
  • Support Sales and Growth teams in pitches with strategic experimentation expertise.

The ideal candidate has the following qualifications, but we encourage you to apply even if you feel you do not meet 100% of the requirements below.

• 7+ 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.

Hybrid work environment

• Private Medical Insurance
• BUPA Life Assurance
• Income protection
• Employee Assistance Program
• 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 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. We believe that diversity and inclusivity make our teams better, so it is our priority to create an equitable and inclusive workplace where our goals, initiatives, and commitments to action are shaped and strengthened by our team’s voices. Putting People First, one of our core values, means we never lose sight of humanity, care, and impact.

Disclaimer: we never request any form of payment or fees from candidates at any stage of the recruitment process. If you are contacted by anyone claiming to represent our company and asking for money or personal financial details, please report it immediately to people@thisisgain.com. All genuine communication will come from official company channels.