A standard / benchmark test for user familiarity or proficiency with computer technology in usability testing

When conducting usability testing, a variable that comes up is the competence or familiarity of different users with Internet or software application technology. It seems strange to compare different usability studies and results if there are no indication of the type of users that are being tested. Is there a standard test used to establish a baseline for user competency or proficiency with general computer technology? I imagine this would be useful for older users that may not have had as much exposure to computers and working out how much different there might be in terms of looking at task completion rate and task completion time.

I am interested in whether this is a standard item provided in a usability report or carried out as part of usability testing screening, and if so then whether there is a standard that is commonly used or if it is generally product/project specific.

Update: Looking at the 2007 Microsoft Office Fluent UI Study Information Workers by Forrester, I noticed that they included a definition of General versus Advanced users by asking two questions about Microsoft Office Product usage and also showing them examples of advanced features. Only people who fit in the criteria for advanced users are classified in that category. Could something similar be developed and standardized for usability testing in general?