How do you calculate the conversion in registration?

Question

Conversion

Colleagues, help out! We have already broken our heads over the problem of correctly calculating the conversion in registering a web service for a mass audience.

Everything seems to be simple - we take Google Analytics, pass the registration event to it, set the goal for this event. This is how we easily find the absolute conversions achieved. And how does the analyst calculate the percentage? Probably calculates the ratio of the number of registrations to the number of new users (who visited the service for the first time).

But that's not the problem - who are the new visitors?
Intuition suggests that these are those who do not have analytics cookies. Well, after all, the cookie disappears from time to time (and the more users we have, the greater the proportion of such “pseudo-new” visitors).

After that, we began to subtract those who logged in from all new visitors.

And then we managed to count all the numbers on the server side (however, the number of unique visits was taken from kissmetrics ). And there are new meanings. We think that on the server side, the data is more accurate (and clearer).

And we have not taken into account the failures! After all, if the user was on the site for only a few seconds, then this means that he is not the target. And here the claim is to traffic, and not to the site (the process of converting traffic in registration). That is, accounting for bounces will allow you to more accurately assess the impact of site changes on conversion.

Therefore, we decided to ask: what solution will satisfy the following requests:
1) spinning on our server;
2) has a mechanism for calculating metrics so that you can specify how to calculate a complex parameter from simple ones;
3) builds understandable graphs .

An additional plus will be the ability to build funnels, conversion sequences, accounting for returns (cohort analysis).

Answer 1

We set a unique cookie for each visitor (value - GUID ) for a year. Each time the page is opened, we update the value for another year. Naturally, if someone deliberately wiped their cookies, then it will be counted as a new visitor, but nothing will help in this case.

Answer 2

maybe help about the cookies that GA sets and here 's more about their lifetime