Is the promotion system fair?

If it was fair, it would be called Welfare, not Army. As a SSG you're expected to be good at your job. Great even. That's why you got promoted. Those who step up and take specialty assignments are showing that they can perform successfully outside their MOS. If you have two people and only room to promote one, you promote the one that has shown they can handle anything, anywhere, anytime. Not the one who can only perform their job.

SSG (Join to see) Nothing in the military is fair. You can get promoted without having to be in a job that is for a higher rank. I was selected for SFC having never been a PSG. It is all in what in on your NCOERs. Promotion boards look for different things year to year. Don't get hung up on your position but how you are performing your duties.

I had a former CSM and now deputy Commandant at an NCOA brief the board process to us while in ALC and SLC. I attended both while a SSG(P) and then as a SFC. She sat on the board I was selected for SFC, her job in the process was called "cracking the file" first looked at being the ERB, did the Soldier have any assignments or positions above their current grade for a significant time period, did the photo and awards match up etc... If all that did then the file was pushed with a rank score determined by the board for further analysis, if trooper was a solid performer outside of their grade it was looked upon favorably as they already were doing things at a Junior NCO Grade that would be expected of a Senior NCO hence strong candidate for promotion. But with the wars etc we have promoted to many too quick who weren't ready and now some low density MOS's are feeling the brunt with low selection rates. Just my 2/100ths of a dollar