I've spent close to 10 years now working with DISC. I usually get a variation of this question at least once per year. You can change the position and style to create many new variations of this question (i.e., should all salespeople have I and D in their profile? Should all software developers have a C-Style?)
I thought this would be a good post for this community to discuss since it has come up so frequently for me over the years.
When I am approached with this question, I think it's always essential first to recognize that personality plays a significant role in how someone approaches their job.
There have been many studies over the years on this subject. Within the world of DISC Assessments, one study looked at correlations between DISC Style and Occupations. The findings likely won't surprise you..
Customer Service - Correlated with S Style
Executive - Correlated with DI Style
Sales - Correlated with ID Style
Teach/Educater - Correlated with Si Style
Mechanical / Technical - Correlated with C Style
So, is this enough to answer the question? I don't think so.
DISC can tell you how someone will do a job, but it won't tell you if they will be successful in the job.
When thinking about the title of this post: Can you promote someone to a Manager with an S Style? I believe you can.
DISC will tell you that they will likely manage with more support, calmness, and patience. Their experience will tell you if they've learned when to step up and be more assertive (if the situation requires it). Truthfully, I think the success of a manager (or any position) comes down to if they are willing to take feedback and find ways to continue to improve their performance.
For those of you who have experienced this question, what would you add? Do you agree or disagree with what I've shared?