When you're using Polar Analytics to track eCommerce sales data from either Shopify or Amazon, it's important to keep in mind that your "Total Orders" metric differs from your "Product Quantity" metric.
Total Orders refers to the number of individual transactions made, regardless of the number of items purchased in each order. For example, if a customer places three separate orders, the Total Orders would be three (regardless of the quantity of items in each order).
Quantity Ordered refers to the total count of items or products purchased across all orders. It represents the sum of the quantities of items purchased in each individual order. For example, if a customer places three separate orders and purchases two items in the first order, three items in the second order, and one item in the third order, the Quantity Ordered would be 6 (2 + 3 + 1).
With that said, typically when you're looking at a large enough date range, Product Quantity will always be larger than Total Orders. However, keep in mind that Product Quantity in Polar is net of returns, meaning that returns are not included in that metric. Depending on your data settings, returned orders may or may not be included in your Total Orders metric as well. If you're looking at a very small date range, it's possible that you could see a lower number for Product Quantity than Total Orders (depending on the total number of items returned).
The visual below shows you an example of how you could set up a blended order and quantity section within Key Indicators, which overall blended Total Orders and Product Quantity from Shopify and Amazon, as well as unique Quantities from Shopify and Amazon.
The blended metric for quantity in Polar (that sums together the total items ordered from all orders from both Shopify and Amazon) is titled "Product Quantity"
The Shopify metric for quantity (that includes only items ordered from Shopify orders) is titled "Net Product Quantity" as it's net of returns
The Amazon metric for quantity (that includes only items ordered from Amazon orders) is titled "Quantity Ordered" as it's the overall number of units ordered