Time-Series Retail Sales Forecasting

Overview

End-to-end pipeline on a year of daily POS data for a small retail client. Compared naive, seasonal-naive, ARIMA, Random Forest, and Gradient Boosting; explored the global-pool approach from Montero-Manso & Hyndman (2021). Paired with a descriptive sales report (day-of-week, seasonal, by-department) delivered to the client.

Gradient Boosting: MAE $494, sMAPE 13.0% — 24% MAE reduction vs ARIMA