How would you model stock price prediction?
Company: Millennium
Role: Software Engineer
Category: Machine Learning
Difficulty: medium
Interview Round: Technical Screen
## Scenario
You are asked to use machine learning to **predict stock prices** (or more realistically, **predict future returns / price direction**) for a trading use case.
## Questions
1. **Target definition:** What exactly would you predict (e.g., next-day close, next-hour return, direction, volatility)? Why?
2. **Data:** What data sources would you use (market data, fundamentals, news, alternative data)? What is the minimum viable dataset?
3. **Features:** What features would you engineer from the data?
4. **Modeling:** What model families would you consider and why (linear models, tree-based, deep learning, time-series models)?
5. **Training & validation:** How would you split data over time to avoid leakage? How would you tune hyperparameters?
6. **Evaluation:** What metrics would you use (ML metrics and trading metrics)?
7. **Pitfalls:** How would you address non-stationarity, regime changes, data snooping, survivorship bias, and transaction costs?
8. **Production considerations:** How would you deploy, monitor, and retrain the model?
Quick Answer: This question evaluates competency in applying machine learning to financial time-series, covering target definition, data selection, feature engineering, model choice, validation, evaluation metrics, and production considerations.