To quote from mSO, since my request is [pretty much identical][1]:

> I would like to have statistics for the quality of posts coming from
> unregistered versus registered accounts on my site.
> 
> It is my suspicion that people who are willing to put out the effort
> to register an account will also put more effort into writing good
> questions; I'd like to see some evidence for or against this.
> 
> I also suspect that on my site the vast majority of good questions and
> answers come from registered users, but again I'd like to see some
> data.
> 
> Is this already possible through the Data Explorer?  If so, how?  If
> not consider this a feature request.

The reason for this is I am considering proposing that Server Fault stop accepting questions from unregistered users, and I would like to have statistics to analyze as part of that process.


  [1]: http://meta.stackoverflow.com/q/192195/189912