Data Sciences Challenges
Explore data science challenges on Ewance to build skills employers expect from analysts and ML engineers. Work through challenges on data cleaning, exploratory analysis, modeling, and storytelling with data.
Most Popular
- ResearchBeginnerNew
Research Roadmap for Meridian DSP's Bid-Matching Pipeline
Using the VP of Machine Learning's context memo (vp-brief) and the pipeline case file (pipeline-case-file) to ground every recommendation in Meridian's actual system, assemble a…
- Information Retrieval
- Learning To Rank
- Research Synthesis
Open coursework - CodeBeginnerNew
Choose a Hash Table or Trie for a URL-Shortener Cache
Build two caches that satisfy the contract in the cache specification (provided): one hash table using linear probing and one compressed trie, both enforcing the same two-millio…
- Hash Tables
- Trie Data Structure
- Benchmarking
Open coursework - AnalysisBeginnerNew
Model Bogotá's Bike-Share Network as a Graph for Overnight Rebalancing
Using only the supplied station directory, the aggregated origin-to-destination trip table, and the operations brief, build a directed weighted graph where each station is a nod…
- Graphs
- Networkx
- Shortest Path
Open coursework - DesignBeginnerNew
Redesign an Executive Revenue Dashboard for an E-Commerce Marketplace
Interview the CFO, the head of category, and 2 finance analysts for 30 minutes each to elicit the 6 analytic tasks the dashboard must support (e.g. month-over-month variance, ca…
- Dashboard Design
- Visual Encoding
- Task Analysis
Information and Data Visualization Develop in-demand professional skills.
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Why Ewance
- AnalysisBeginnerNew
Index a Slow 90-Million-Row FinTech Reporting Database
Your analysis task is to read the engineering ticket and the six reporting queries in the case file (M1), study the transactions table definition, column statistics, and write w…
- Indexing
- Query Optimization
- Explain Analyze
Open coursework - AnalysisBeginnerNew
Plan and Validate a MySQL-to-PostgreSQL Records Migration
Using the de-identified case record (incident-file-records-office), the representative schema export (mysql-schema-sample), and the anonymized staging extract (staging-records-s…
- Database Migration
- Mysql
- Postgresql
Open coursework - DesignBeginnerNew
Choose a Sidecar Cache Store for a Hotel-Search API
Using the captured workload trace and the platform requirements brief in the provided materials, design a proposal that selects one of Redis, KeyDB, or DragonflyDB as the sideca…
- Nosql
- Redis
- Benchmarking
Open coursework - CodeBeginnerNew
Ship a Production CI/CD Pipeline for a Fitness-Studio CRM Startup
Using the FlexDesk starter service and Dockerfile, the current-deploy case file, and the pipeline requirements spec provided, build a complete continuous integration and continu…
- Ci Cd
- Github Actions
- Container Signing
Open coursework - Browse challenges
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Strategy Analyst
Frame the business question, model the options, build the recommendation. From market sizing to competitive analysis, this role is where strategy consulting meets in-house decision-making.
- DesignBeginnerNew
Design a Verified UART Receiver and Loopback for an FPGA Sensor Hub
Propose and deliver a UART receiver for Helax's sensor hub that meets the functional requirements in the requirements brief (the 'uart-requirements-brief' material): 16-times ov…
- Verilog
- Uart
- Fpga
Open coursework - DesignBeginnerNew
Design a Resilient Bridge Between New Commerce and Legacy SAP
Using the integration requirements case file, design how all five interactions move between the storefront and SAP ECC: order create, pricing inquiry, inventory availability, cr…
- Enterprise Integration
- SAP Integration
- Apache Camel
Open coursework - CodeBeginnerNew
Model a Trading Order Book with Algebraic Data Types in Haskell
Design ADTs for Side (Buy | Sell), OrderType (Limit | Market | StopLimit), Order, Trade, and BookState. Make illegal states unrepresentable (e.g. a Match can never produce a neg…
- Haskell
- Algebraic Data Types
- Property Based Testing
Functional Programming - CodeBeginnerNew
Build a Readable Rules Language for Insurance Policies in OCaml
Design a small domain-specific language that covers the building blocks of policy rules: variables (insured amount, premium, deductible, named perils), expressions (arithmetic, …
- Ocaml
- Domain Specific Languages
- Parser Combinators
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Why Ewance
- CodeBeginnerNew
Convert an Imperative Recommendation Service to Pure Functional Style
Take the Python ranking module (around 900 lines). Identify side-effects (DB reads, cache lookups, logging, time) and lift them to the boundary. Rewrite the ranking core in Scal…
- Scala Programming
- Pure Functions
- Functional Core Imperative Shell
Functional Programming - DesignBeginnerNew
Move an EdTech Platform's 4 Clusters to GitOps with ArgoCD
Using only the materials provided — the migration case file (incident_dossier), the service inventory dataset (service_inventory), and the platform team's target-state brief (ta…
- Argocd
- Kubernetes
- Kustomize
Open coursework - DesignBeginnerNew
Redesign Stadig's Onboarding to Stop the Screen-3 Drop-off
Using the current four-screen flow described in the onboarding flow specification and the funnel numbers in the onboarding analytics dataset, run a heuristic evaluation of the e…
- User Centered Design
- Usability Testing
- Heuristic Evaluation
Open coursework - StrategyBeginnerNew
Build a Tiered Vendor-Security Review Program, Validated by a 12-Vendor Pilot
Using the de-identified subprocessor inventory and the twelve-vendor pilot dossier provided, design a three-tier risk program (critical, important, low-risk) with explicit, obse…
- Third Party Risk
- Security Governance
- Compliance
Open coursework 
CodeBeginnerNewBuild a Search-Based Delivery Router for a Madrid Grocery Startup
Build a Python service that exposes a single /route endpoint. It accepts a courier's starting location, a list of delivery stops, and a traffic window, and returns the stops in …
- Search Algorithms
- Intelligent Agents
- Python Programming
Open coursework
CodeBeginnerNewKnowledge-Graph Recommender for a Lisbon Bookstore
Using the catalog sample (catalog_sample), build a knowledge graph whose nodes are books, authors, genres, themes, eras, and awards, and whose edges capture relationships such a…
- Knowledge Representation
- Knowledge Graphs
- Python Programming
Open coursework
CodeBeginnerNewBuild a Pricing-Aware Scheduling Agent for Smart Thermostats
Using only the materials provided, build an intelligent agent with four working parts: perception (read the sensor history), learning (cluster each household's comfort intervals…
- Intelligent Agents
- Basic Learning
- Python Programming
Open coursework- CodeBeginnerNew
Churn-Prediction Model for a B2B Vertical SaaS
Use 18 months of anonymized data (provided) covering: usage events, login frequency, support tickets, NPS responses, billing health, feature adoption, practice firmographics. De…
- Supervised Learning
- Python Programming
- Ml Applications
Machine Learning (CS Elective) - AnalysisBeginnerNew
Customer-Segmentation Study for a DTC Subscription Box
Use 18 months of anonymized data: order history, churn events, NPS responses, box-rating data, referral activity, marketing-channel attribution. Engineer features (RFM-style + b…
- Unsupervised Learning
- Python Programming
- Ml Applications
Machine Learning (CS Elective) - CodeBeginnerNew
Build an Embedding-Based Semantic Search for a Legal-Document Corpus
Embed the 380k-document corpus using a multilingual sentence-transformer (e.g. multilingual MPNet or LaBSE). Store embeddings in FAISS or pgvector. Build a search service that r…
- Deep Learning
- Ml Applications
- Python Programming
Machine Learning (CS Elective) - DesignBeginnerNew
Establish IT Governance for a Hyper-Growth Consultancy
Analyze 18 months of SaaS expense data and the failed client-audit report to identify the top 5 governance gaps. Design a framework covering: SaaS procurement (who approves what…
- It Governance
- Saas Management
- Access Management
IT Management and Governance - StrategyBeginnerNew
Launch Plan for a Bootstrapped Journaling App Across Two App Stores
Your task is to act as the launch product manager and turn the team's raw position into an executable plan. Read the launch-readiness file (LAUNCH-FILE) to understand the team, …
- App Distribution
- Store Listing
- Mobile Analytics
Open coursework
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