Data Science Lead

We're hiring a Data Science Lead in London to build and lead our Predictive Growth Optimization team - pioneering ML models that power our user acquisition strategy, predict lifetime value, and optimise our $25M+ annual marketing spend across channels. This role owns the strategy, development, and continuous improvement of Flo's pLTV system - a mission-critical model reused across UA, AdTech, personalization, and financial forecasting. You'll balance hands-on technical leadership with people management, building production systems that directly impact our growth trajectory.

Flo is the world's #1 health app on a mission to build a better future for female health. Backed by a $200M investment led by General Atlantic, we became the first product of our kind to reach a $1B valuation in 2024 - and we're not slowing down.

We're a mission-led, product-driven team. We move fast, stay focused and take ownership - from brief to build to impact. Debate is encouraged. Decisions are shared. We care about craft, ship with purpose, and always raise the bar.

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• Lead & develop a team of 4+ ML and Backend engineers - hiring, mentoring, and setting technical direction
  
• Own pLTV strategy - architect and evolve our core predictive lifetime value models that inform millions in UA decisions
  
• Build production ML systems - from MMM algorithms to real-time forecasting models handling millions of daily predictions
  
• Drive cross-functional impact - partner with Growth, Product, and Finance to translate business problems into ML solutions
  
• Shape technical architecture - guide MLOps infrastructure, monitoring, and rapid iteration cycles
  
• Stay hands-on - contribute to modeling, architecture decisions, and technical problem-solving as needed
  

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• 7+ years applied ML experience building and deploying models in production
  
• 4+ years managing technical teams (ML engineers, data scientists, or similar)
  
• Expert knowledge of ML fundamentals: supervised/unsupervised learning, time series, causal inference
  
• Experience with modern ML frameworks (PyTorch, TensorFlow, scikit-learn, CatBoost)
  
• Growth & Product Experience
  
• Experience with growth analytics, attribution modeling, or marketing effectiveness
  
• Understanding of user acquisition funnels and retention optimization
  
• Comfortable translating business requirements into technical roadmaps
  
• Strong communication skills - can explain complex models to executive stakeholders
  
• Production ML Systems
  
• Experience deploying ML models at scale (millions+ predictions/day)
  
• Knowledge of MLOps practices: model versioning, monitoring, automated retraining
  
• Understanding of data engineering fundamentals and cloud platforms
  
• Experience with Marketing Mix Modeling, attribution, or ad tech
  
• Background in consumer tech, mobile apps, or health tech
  
• Knowledge of privacy-preserving ML techniques and A/B testing methodology
  

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• Competitive salary and annual reviews
  
• Opportunity to participate in Flo's performance incentive scheme
  
• Paid holiday, sick leave, and female health leave
  
• Enhanced parental leave and pay for maternity, paternity, same-sex and adoptive parents
  
• Accelerated professional growth through world-changing work and learning support
  
• Flexible office + home working, up to 2 months a year working abroad
  
• 5-week fully paid sabbatical at 5-year Floversary
  
• Flo Premium for friends & family, plus more health, pension and wellbeing perks