After the previously released Beijing housing vacancy numbers caused a lot of internet chatter, The Powers That Be in Beijing apparently felt the need to use the press to do some damage control (see here 北京警方：空置房概念基于电子地图 与房地产无关 and here 中国网事）房产空置率到底有多高？——“北京空置房屋３８１．２万户”引网络热议, via Sinocism.com). Combining the data from various articles I think there is now enough information to come up with a more reliable estimate for Beijing residential vacancies.
The previously reported vacancy numbers were based on their Orwellian mapping project, which this article, The Beijing Police Have an Electronic Map That Shows Where You Live, says is 87.7% complete. To date 4.269 million housing units have been assigned to people in the mapping project. Assuming a constant assignment rate the remaining 12.3% of the survey should reduce vacancies by ~600K, and the previous 3.812 million vacancies becomes ~3.2 million.
Since it’s now said there are 13.205 million existing housing units, the vacancy rate can be calculated as 3.2/13.205 = 24.2%. Still quite high, but certainly more believable. Then there is commercial…
**One of the above articles claims 28.9% vacancies but uses the earlier [unadjusted] vacancy number of 3.812 million.