A psychologist named William Marston created a way to rank personality traits according to 4 main behavior styles. Everyone has all 4, but the degree of each style and the blends between them differ from person to person. Marston called his ranking system DISC, an acronym of the 4 styles:
I took my first DISC assessment and class in 1984. The class was sponsored by the National Association of Music Merchants, or NAMM. Out of all of the profiling and communication classes that I have taken at dozens of seminars in the years since (some of which took the fundamentals of DISC and simply renamed them), I still consider it the single most important business class I have ever taken, and I have shared it with every team I have managed since.
It's probably no secret to you that individuals with a strong 'C' drive tend to end up in Accounting, high 'S' individuals tend to gravitate to IT, 'I' to Sales and PR/Marketing, and high 'D' to Management, but this is a black-and-white perspective of a shades-of-grey reality. High incidence of these traits make these employees well-suited to their roles. They would not be as good at what they do as they are if their personalities were different. Unfortunately, this often means that communication between different departments is strained, because the personalities and communication styles of the people involved are so different from each other.
Communication with external Customers is just as difficult. Salespeople with high 'I' may actually turn off Customers who are high 'C'. Customer Service reps who are high 'S' may frustrate high 'I' Customers. Every behavior style wants to be spoken to in its own native language. Isn't that what you expect as a Customer? And what's wrong with that?
For this reason, I recommend DISC profiling and training for all employees, beginning with Management, then PR/Marketing (if they haven't already had it), Sales, Customer Service, IT, Accounting, Development, Production, etc. Profiling so that each employee is aware of how they are perceived and what their own needs are, and training so that they understand other styles and learn to communicate with them in their own language.
Be aware, too, that certain behavior styles can have a tendency to bugger advancement and chain of command. For example, people with high 'I' personalities tend to move up quickly because they are social animals and often well-liked. But they also tend not to be detail-oriented or results-driven. Why advance someone into a management position if they are not likely to be any good at it? This does no one any good. By the same token, someone with a high 'D' personality has a tendency to believe that codes of conduct and process do not apply to them. Is that who you want as your CEO?
Again, people are rarely this black-and-white, nor am I saying that a high 'D' person can't be a good CEO (especially if paired with a high 'S' COO). Everyone is a blend. Just be aware of how different behavior styles can influence your thinking when hiring, managing, and promoting.
An overly complicated DISC matrix. (I had a little trouble with the scissors.)