Online ISSN 2286-0266
Print ISSN 1223-0685
© 2026 Œconomica by ASE & SOREC
 
Ana Octavia ALBU
Academia de Studii Economice din Bucureşti
This paper examines how promotions and holidays affect forecasting risk in perishable food retail. Using daily sales data from the Corporación Favorita dataset, the study analyses three stores and ten perishable product families during 2016. The focus is on over-forecast errors, defined as cases in which predicted demand exceeds actual sales and may therefore create excess inventory. A seasonal naïve model is compared with Random Forest and XGBoost forecasts. The results show that promotions and holidays both increase over-forecast errors, with holidays producing the greatest instability. Machine learning models reduce the magnitude of these errors compared with the seasonal naïve benchmark, but remain vulnerable during event-driven demand shifts. The findings also show that conventional accuracy metrics can lead to different conclusions from waste-oriented indicators. While the seasonal naïve model performs best according to MAPE, XGBoost produces the lowest estimated waste. The paper argues that forecasting systems for perishable goods should be evaluated not only by average prediction accuracy, but also by their behaviour during high-risk retail events. This perspective is relevant for retailers seeking to align demand forecasting, inventory control, and food waste reduction.

ŒCONOMICA no. 1-2/2026
Keywords: perishable food retail, demand forecasting, machine learning, over-forecasting, food waste
JEL: C53, L81, Q18, Q56
When Accurate Forecasts Still Produce Waste: Demand Shocks and Over-Forecasting Risk in Food Retail