Recently a customers asked about getting historic data into Google Analytics:
I'd love to know how to get Shopify data (prior to embedding Google tracking code) on to Google Analytics to see previous years data.
At first I didn't think that was possible but after a bit of searching I found Google's Data Import that supports adding that data and other data.
It'll probably be a significant project getting all of that data correct, but for important data it might be worthwhile.
One useful thing about Repeat Customer Insights is that it'll import all of your order and customer history automatically. That full history makes the results from its algorithms more useful and gives you a clearer picture on your customers.
Eric Davis
Discover where your best customers come from
Going beyond simple attribution, Repeat Customer Insights lets you analyze and segment your customers by who first sent that customer your way.
This will let you find the best sources of long-term customers, not just anyone who orders.