Google Analytics is a powerful integration, and sometimes can be a bit complicated. Here are some handy things to know to help you get more value out of it.
Grow uses the exact same data as Google Analytics. Sometimes Google Analytics restricts the amount of data it returns when a query includes a large number of dimensions or a large amount of data. In other words, if your data for a particular web property within a given date range exceeds a certain number of visits, GA will aggregate the results and return a random subset of that data, called sampled data.
We have a full article about reducing or eliminating sampling---check it out!
Using Different Date Ranges
Sessions and other metrics will change slightly due to longer date ranges, due to how Google calculates things.
You can see this sometimes if you run a MTD sessions report day by day. You can look at the 5th day of the current month, and note the # of sessions. Then if you change the date range to the start of last month, and look at your previously chosen day, and compare the #'s, they can be off slightly. Since this is calculated by Google it calculates it consistently, so the slight changes should not affect your data. But it is useful to know why it is happening.
Google Analytics API v3 or v4?
99.9% of all Google Analytics metrics are made with v4 of the API. You can ignore v3 unless you know you have some legacy system that relies on it so you haven't switched over. Grow offers both version 4 and version 3 just in case, but you should use v4.
Questions? Let us know at firstname.lastname@example.org or chat in on the site.