I researched Google's algorithm a while back and a a fairly strong ranking factor IS how long they spend on your page/site (whether you have GA or not) but that can backfire. (I know that Google's exact algorithm is unknown but it's based on experiments by SEO sites)
Here's how I understood it to work:
If a user finds you on a Google search and then clicks the link, Google times how long it takes for you to come back to the search results. So if you immediately backed out of the page they would take that as meaning the result was crap and they took that into account in their algorithm. The thinking being that it was an irrelevant result.
However, that counts against sites that provide the answer you want right at the top of the page so that when you open the page, the answer is staring you in the face... so obviously you are going to back out again as you have your answer.
This was from around two years ago when I was researching building an indexer and search engine for kicks so my memory of how it worked is fuzzy.
If only Google had a technology that would preload the top results (maybe coming from a Google CDN) and show them right on the search results page. I’d be AMP’ed for that.
Users may back out again once they have the answer, but they probably won't click on another search result. This should show Google that the user found their answer on that page.
Every google search result you see is masked to have a boat load of tracking that identifies you, your search query and a variety of other details. When you click out from Google you are first bouncing through Google's instant redirect before you are taken to the target website.
When users click the back button they bounce back through the redirect to the SERP.
You can test the tracking by right clicking and copy/pasting the URL of any Google search result. This can be stripped using add-ons (and I highly recommend it).
Here's how I understood it to work:
If a user finds you on a Google search and then clicks the link, Google times how long it takes for you to come back to the search results. So if you immediately backed out of the page they would take that as meaning the result was crap and they took that into account in their algorithm. The thinking being that it was an irrelevant result.
However, that counts against sites that provide the answer you want right at the top of the page so that when you open the page, the answer is staring you in the face... so obviously you are going to back out again as you have your answer.
This was from around two years ago when I was researching building an indexer and search engine for kicks so my memory of how it worked is fuzzy.
Also, it may have changed.