Use this skill when
- •Analyzing data with a temporal component (timestamped data).
- •Performing forecasting (predicting future values based on history).
- •Detecting anomalies or change points in time-evolving systems.
- •Engineering features from time series (lags, windows, Fourier transforms).
- •Dealing with stationarity, trend, and seasonality issues.
Instructions
- •Check for stationarity (ADF, KPSS tests) before applying linear models.
- •Use Cross-Validation specifically designed for time series (TimeSeriesSplit).
- •Account for Seasonality (Daily, Weekly, Yearly) and Holidays.
- •Prefer ensemble methods or hybrid models for complex real-world data.
- •Evaluate models using temporal-specific metrics like MAE, RMSE, MAPE, and MASE.
Capabilities
Traditional Statistical Models
- •ARIMA/SARIMA/SARIMAX: Classical linear forecasting.
- •Exponential Smoothing: ETS, Holt-Winters for trend and seasonality.
- •VAR/VECM: Multivariate time series and cointegration analysis.
- •GARCH: Modeling volatility in financial time series.
Modern Forecasting Frameworks
- •Prophet (Meta): Automatic forecasting for business data with holiday effects.
- •NeuralProphet: Hybrid Prophet/PyTorch models.
- •sktime / Darts: Unified APIs for time series machine learning.
- •StatsForecast / Nixtla: High-performance statistical forecasting at scale.
Machine Learning & Deep Learning
- •Gradient Boosting: Using XGBoost, LightGBM, or CatBoost with lag features.
- •Recurrent Neural Networks: LSTM, GRU for long-range dependencies.
- •Temporal Fusion Transformers (TFT): Advanced multi-horizon forecasting.
- •DeepAR: Probabilistic forecasting with Deep Learning.
Temporal Feature Engineering
- •Lag Features: Creating shifted data points (L1, L7, L30).
- •Rolling/Expanding Windows: Mean, Std, Max over time intervals.
- •Fourier Transforms: Converting time domain to frequency domain for seasonality.
- •Calendar Features: Extracting day of week, month, payday, etc.
Example Interactions
- •"Analyze this sensor data for anomalies and forecast the next 24 hours."
- •"Build a Prophet model to predict retail sales, accounting for Black Friday."
- •"Perform a stationarity test and decompose this series into trend and noise."
- •"Convert this multivariate time series into a supervised learning problem for XGBoost."