Examining all widely-sold products in a large, national scanner database, we find that seasonality in demand is large, pervasive across product categories, and heterogeneous in its timing. Yet at seasonal frequencies prices fluctuate little, and typically, countercyclically, falling as demand...

Agent-based models can replicate real-world patterns, but finding parameters that achieve the best match can be difficult. To validate a model, a real-world dataset is often divided into a training set (to calibrate the parameters) and a test set (to validate the calibrated model). The...