How do CSMs select the best future SFCs of the Army?

SSG Moore, we really look for the one who has done better than the average bear...beyond the ordinary. Too many people think they should be promoted for what they have done, not for what they are expected to do!! Your record should indicate your potential and your ability to live up to your potential. How do you communicate that? How many happy soldiers do you see in a file photo? Looking stern and tough is fine, but do you exude confidence and competence? You met the standard if we are looking at your file. I want to promote you, and I am not looking for reasons NOT to promote you. Sometimes we have to look at it that way to cull the herd later, but it's a very fair process.
In my case we draw a line and then relook people just above and below it in both zones. People do get moved up to meet standards, goals, career field gaps and looking to the future. If you make SFC you can make Sgt Major. But the competition gets keener, with more qualified people at each level (you know the song about statutory limits on the number of E8s and E9s (1 to 3 percent or whatever it is now).
If I am looking at six staff sergeants who all have the same career track, nice NCOERs, PT, similar awards, the standard.... it might come down to how one looks in uniform, whether ribbons are correct, how many times they've been deployed or overseas--and of course how well you did there. Were you in a higher graded position? What does your past record say about your future success. But the fellow who stands out is often the one who added something new to his/her record each year--someone who made an investment in the Army and who the Army made an investment in. Folks in the 'tough' jobs surely do get moved up--but with today's tempo all jobs are tough. It's what you did in the job, how you improved yourself that impresses me if you want a 6+++++ vote. Special, nominative Assignments put you in another class; they tend to also follow a career track. So volunteer through your branch or get nominated any one you can (SHAPE, DOD, embassy, instructor, etc).

It's a mishmash of inconsistent reasons that only THEY know, and it changes every year, for reasons ONLY they know, and will never fully explain. Yes, I'm bitter, and angry, that I'll retire an E-6. But then I watch people make it on first looks who couldn't march their way out of a shithouse. It's not even just me. I've seen guys and gals who are 10x more deserving as I not make it.

Who knows what they're thinking when they make selections. Probably just a wall, blindfolds, and a dartboard.

SSG Moore, fortunately we will soon have a better answer to your question. The changes to the NCOER will allow boards to truly see who is the best among the force as compared to their peers. Not just the right jobs, but whether they were above the center of mass versus just some subjective random bullets which justify a non-controlled box check. "Strong NCOERs" are relative. I have seen very few weak NCOERs. Only a handful of mediocre NCOERs. The rest are strong. I'd say about 70-80% of them. That's way over the "center of mass" ideology. I'll be glad to finally see some rigor in this sytem.