'Placement', as the name says, is all about event placement (e.g. ammo spammed or not/springs put in appropriate areas, etc). Just like if you have a bad habit of putting ammo in the wrong areas/spamming it, 'placement' means if you are or aren't very good at placing ammo/events.
For example: if you run out of ammo or are in need of a Full NRG carrot in CTF, you should easily be able to find ammo, but it shouldn't be spammed. Same with the Full NRG carrot, except those need to be harder to find/harder to control.

Also:
You don't mean the 'Fastest Improver Jimbob' part as well, right?