Continuity mistake: Abby says that McGee is the most helpful person with clipboards. When she does, the position of the clipboard in her arms is constantly changing between instant cuts. (00:03:30)
Continuity mistake: When we first see young Abby, the way she's holding her bear changes between shots. (00:04:50)
Continuity mistake: In the evidence locker, Ziva opens a folder and the white notepad is on the left-hand side. Camera changes to behind her, and now the white pad is on the right. (00:26:40)
Chosen answer: It is never stated, however she must have been there several years if she is on presidential detail.