0. CS Commission sets a minimum written score for oral interviews. Score is arbitrary and largely designed to limit number of interviews to an acceptable number (20-30 total per vacancy).
1. Commission asks applicants the same questions, in the same order, asked by the same commissioner. Scores are subjective but on a 1-7 scale.
2. Does the mean score surpass the 60% pass rate? If yes, applicant moves to next step.
3. Does the applicant, in their background investigation or oral interview, admit to any explicitly listed disqualifying acts as listed in the Commission's rules & regulations? If no, applicant moves to next step.
4. The written and oral scores are averaged based on a prescribed weighted formula. This weighted score is 0-100.
5. Is the applicant a veteran? Add a certain number of points.
6. Give the top three names to the hiring body (varies by position).
7. Is a veteran in the top three? Guess what, they get the job no matter what.
This question obviously only applies to a subset of veterans. There's a civilian analog to many military jobs and the military's training and experience in those fields can stand on its own without preferential treatment for the most part.
A combat veteran may make a good post office manager or a good cop but it's probably better off for everyone if he's only given preferential treatment in the latter role.
In practice, the veterans benefit becomes meaningless once you advance in specialist grades (GS-09+). But it will get you the glorious position of elevator operator in Carlesbad.
There's two ways this is true in state and/or federal government:
(1) hiring into specific programs which are essentially designed as welfare hiring programs (these aren't big today, but there are a few of them still.)
(2) special, broadly-applicable civil service hiring preferences (mainly for certain disabilities and military veterans.)