The "Population" part of Population Health

So I tried to skip over the Population part of Population Health Management yesterday, but my incredible pediatrician wife pointed out that actually knowing who is in "your population" can be downright impossible.  

First, maintaining a list of people with accurate demographics including contact information is still very hard in 2015.  In addition to simple names, addresses and ages--all of which can change over time even with perfect data fidelity, we have to add a status to that list.  Are you a patient of Dr. Schutzbank?  Do you have Masshealth insurance?  Since when? When does or did that change?  

Outside of health care, we do this well and we call it Facebook.  Everyone ensures that their information is updated regularly.  However, Facebook is voluntary and the information is necessarily interesting to the poster.  Sharing pictures of vacation may motivate me to log in, find the photo, upload it, tag it, etc.  Updating my primary care doctor selection is just not that interestin…