Find threshold in rate to determine reason for lost customer I'm not sure if anybody will be able to help with this, or even if I'll be able to explain it well but I am stuck so here goes....

I have a set of customers, some are lost, some are still active. We have a model which looks through the data and assigns reasons for why they became lost. One of the reasons to determine is if them not using our software caused them to become lost - we have software to automate their orders but they can ignore this and process orders manually.

I have created 2 variables; software usage rate and software usage vs their country average (as a ratio). 

My aim is to determine the point, in either or both of these, which is basically the threshold/marker to say the software was an issue. I am stuck as there are in essence no results - we know if a customer is lost, but we can only speculate/model on the reasons. 

All I've been doing so far is looking at the distributions of lost and active manually.

Any help would be great.

Thanks
You could use a two-sample $t$-test to determine whether software usage is significantly lower for lost users.

Plotting 'software usage rate'/'software usage rate relative to country average' against 'percentage of lost users' might give you an idea about a suitable threshold.