DEMAND FORECAST
Definition
Demand forecasting is the process of predicting future sales volumes for a product, category, or retail location over a given time frame (day, week, season). It relies on sales history, external variables (weather, calendar, competition), and, increasingly, machine learning models. It forms the foundation of sales planning, purchasing, and pricing strategy.
Why it's important
- Optimizing inventory: Accurate forecasting prevents stockouts (loss of revenue) and overstocking (tied-up capital, damage).
- Tailoring promotions: Understanding natural demand allows you to measure the incremental effect of a promotion.
- Managing margins: adjusting prices based on projected demand maximizes revenue (yield management).
A concrete example
A clothing retailer forecasts demand for its summer collection starting in January. The models incorporate data from the past five years, fashion trends (NLP analysis of social media), regional weather forecasts, and the sales calendar. For a specific T-shirt model, the forecast is for 28,000 units for the season, with a peak in mid-June. This forecast guides supplier purchases (32,000 units ordered with a 15% margin), logistics planning, and promotional windows.
How to measure/use it
A robust forecast combines several approaches: traditional statistics (moving averages, ARIMA, Holt-Winters), machine learning (gradient boosting, recurrent neural networks), and business expertise (category manager judgment). Modern tools use hybrid architectures that weight these sources based on the context. Accuracy is measured by MAPE (Mean Absolute Percentage Error), with typical targets ranging from 5% to 25% depending on the product’s stability.
Common Mistakes
- Underestimating external factors: a model that doesn't account for weather, holidays, or competitors' promotions misses key variations.
- Forecast at only one level: forecasts must be available at the SKU, store, and category levels, with consistent trade-offs.
- Failure to measure performance: without monitoring the MAPE and conducting regular back-testing, it is impossible to know whether the model is deteriorating.
Learn more
- Research & Data: Using AI for sales forecasting to build robust models.
- Solutions: Pricing Analytics to link demand forecasting with pricing decisions.
- Tip: Pricing training to equip your teams with the skills to interpret forecasts.
- Resources: Check out our pricing FAQ to learn how to combine forecasting and yield management.