Average Order Size is calculate by dividing the number of units (or products) sold by the number of transactions (purchases) to see the average number of items per purchase. Similar to Average Order Value (AOV), Average Order Size (AOS) can be a good indication of an ecommerce business' sales success – specifically their ability to up-sell or cross-sell.
You know how many stores have candy at the checkout counter? That's one brick-and-mortar method of increasing both Average Order Size (AOS) and Average Order Value (AOV).
Ecommerce businesses can drive up their Average Order Size (AOS) by creating and implementing various upsell elements and adaptive experiences on their site such as unique carousels on every PDP with complementary product recommendations or carousels with a one-click, multi-item, add-all-to-cart functionality.