There are numerous meta posts about the huge close review queue on Stack Overflow.
But SO is not the only site which is struggling with its close review queue. Several other sites have a lot of items (on their own scale) at any given time in their close review queue while the other queues are pretty much empty. Here are the number of items in the close review queue and the total for the other queues right now on the highest-traffic sites plus a few (I cut off when I got tired and added CS which I'm personally familiar with and Chemistry and Scicomp for comparison):
site 2014-Jan-02
queue close others
SO 100970 1
Gaming 2 6
SU 384 8
Ubuntu 178 11
Apple 0 6
English 6 4
Cooking 5 9
SF 59 4
Android 1 3
Webapps 9 2
Unix 2 0
Math 0 4
SF&F 1 4
Programmers 51 6
TeX 0 0
Bitcoin β 40 24
DIY 2 11
EE 2 0
DBA 2 0
Security 0 0
Movies β 0 2
RPi β 21 29
Wordpress 1 4
CS β 33 5
Chemistry β 0 0
Scicomp β 6 5
So among SO, SU, SF, AU, Programmers and CS seem to have a difficulty with the close review queue. The other sites don't. For the sites I frequent (SO, AU, CS), I can confirm that this situation is habitual.
Is there a common factor that makes close reviews more difficult or less attractive on certain sites? Do items linger for a long time or is the high queue size due to a lot of items lingering there?
And of course the habitual question — what can be done to improve things, that hasn't already been suggested (or that has and is specifically relevant cross-site)?