INTERNSHIP: Data Science

We’re hiring aPython‑first, statistics‑strongData Science Intern (or junior ML Engineer) to partner with ourData Analystson the hardest problems we have:probabilistic LTV ,churn prediction , andforecastingthat actually moves CAC, payback, and ROAS.⚠️ READ THIS FIRST — Apply only if you meet this: Eligibility: You’re currently studying at a university in Spain (ideally in or near Barcelona) and can sign a "convenio de prácticas". This position is open exclusively for internship agreements. If you’re not sure whether your university can provide one,please confirm with them before applying , as we’llautomatically filter out candidates who can’t meet this requirement. Otherwise, feel free to check out our otherjunior roleson the Carrots Lab LinkedIn page › Jobs where a "convenio" isn’t required.⭐ WHAT YOU’LL OWN (Your Mission) LTV Prediction & Probabilistic Forecasts Build, compare, and iterate LTV models (e.g., survival/retention‑based, zero‑inflated + Gamma, GBMs). Producecalibratedpredictions we can trust for UA and pricing. Churn & Retention Modeling Predict churn windows and retention curves by app/geo/cohort to inform payback and creative/keyword strategy. Signal Engineering for UA Translate model outputs intoconversion signals(e.g., value‑based bidding targets) that improve Google/Meta optimization. Revenue & Cohort Analytics (Python) Pull, transform, and join event & purchase data (RevenueCat, AppsFlyer, Firebase, BigQuery) into model‑ready datasets. Decision Science Evaluate A/B tests (frequentist or Bayesian), pricing experiments, and funnel changes withconfidence intervalsandpractical uplift .WHAT SUCCESS LOOKS LIKE (90 Days) LTV v1 shippedper flagship app with baseline vs. model comparison (e.g., MAE/RMSE or calibration plots) and a documented retrain cadence. Churn or retention model v1that beats naive benchmarks (e.g., 30‑day retention mean) and informs UA payback assumptions. Signal specdelivered: which in‑app events/values we should pass to ad platforms, how to weight them, expected CPA impact. Reproducible codebase : clean notebooks/scripts with README, functions, and basic tests; data pulls automated in Python. Live dashboards(with Sergi): LTV/payback & cohort views wired toLookerfor weekly decision‑making.WHAT YOU’LL DO (Day‑to‑day) WritePythonevery day: data prep, feature engineering, modeling, evaluation, and reporting visuals. Query data fromBigQuery/RevenueCat/AppsFlyer/Firebasevia Python; assemble tidy training datasets. Train and compare models (e.g.,linear/GLM ,XGBoost/LightGBM/CatBoost ,survival analysis ,time‑series ). Calibrate predictions (Platt/Isotonic), monitor drift, and set up retraining logic. Package insights forUAandProduct : concise memos, charts, andclear “so‑what”recommendations. Pair withSergi(analytics & viz) and theCEO(UA/product strategy); own the technical depth.️ WHAT YOU MUST HAVE (Hard Requirements) Non‑negotiable. Please apply only if you meet all. Python : strong hands‑on withpandas, NumPy, scikit‑learn, Jupyter . Statistics & ML : probability, hypothesis testing, regression, classification, evaluation & calibration. Project evidence : at leastoneend‑to‑end model you can show (repo/notebook; academic is fine if applied). Autonomy & speed : ability to self‑direct, research, and ship working code without step‑by‑step guidance. Communication : explain complex modeling choices in plain language, with actionable conclusions. Availability : full‑time inBarcelona(hybrid),6+ monthscommitment. Work authorization : able to work in Spain (student internship agreement or junior contract).NICE‑TO‑HAVE (Great to see) Bayesianmodeling (PyMC/Stan),survival analysis(lifelines),time‑series(statsmodels). Gradient boosting(XGBoost/LightGBM/CatBoost) and model calibration. Experience withBigQuery(via Python),RevenueCat ,AppsFlyer ,Firebase ,Amplitude . BasicGit , packaging, and testing discipline. Prior exposure tosubscriptiondatasets (trials, renewals, cancellations, grace periods).HOW WE WORK Stack : Python, BigQuery, Looker, RevenueCat, Firebase, AppsFlyer, Amplitude, Google Cloud. Cadence : weekly experiment reviews; model metrics > opinions; minimal meetings; fast iterations. Culture : high speed, high standards, zero drama. We spend every euro like it’s our own.WHAT WE OFFER (Compensation & Benefits) We offer a high-impact, high-autonomy role with a reward structure aligned to the company's growth in Barcelona. Paid Internship:This is aremunerated full-time positiondesigned to give you real ownership and impact — not just “student tasks.” The compensation iscompetitive for top data students or recent graduatesin Barcelona. Flexibility & Time Off:Flexible working hours , 25 days annual leave, and1 month of 'work from anywhere'outside of Spain. Executive Workspace & Tech:Private offices atNorrsken House Barcelona(with complimentary membership) and a generous€5,000 EURbudget for professional home-office equipment. Wellness:Option to require a high-end Gym Membership at innerflow.es, including Spa Access in the same office building. Cantina : Delicious, healthy, and flexiblein-office catering— meals starting at just €2–€3. Training:DedicatedBudget for an education program . Career Trajectory:ATailored career planwith performance reviews and salary calibrations every 6 months.If you made it all the way down here… Stop looking for entry-level jobs where they’ll spend six months “onboarding” you to clean up spreadsheets. Come here and build real things from day one. Worst case? You’ll leave smarter.Carrots Lab is an equal opportunity employer that celebrates diversity. All applicants will be considered regardless of race, color, ancestry, religion, sex, national origin, sexual orientation, age, disability, gender identity, or expression.