I can not do this myself as I am a victim of a previous RA, but I wonder what would happen if a person used a wild card search "," in the IBM directory name field (use to be called Blue pages,) to search for . in the United States . How many names would come back meeting that criteria? You could also refined the search to regular employees, this would exclude contractors. This would establish a baseline. And if you did it periodically ( monthly & quarterly) you could see trends which would provide some anecdotal information of the impact of RAs on the IBM US employee population. A programmer or Data Base Administrator might have a better idea on how to gather this data for analysis
One could also do the same for a different geography , say for example India.
Just a thought.