What are the consequences of ingroup and outgroup categorization?

Question 1
Perform some research on other personality tools (HBDI, Insights, Birkman, 16PF). Why do you think companies can benefit from using these tools? Do we really hire people based on mirror images of ourselves? Why could this be a risk for a project manager?
Question 2
What are the consequences of ingroup and outgroup categorization? How does this categorization affect a person’s behavior in a group or team? Please find a business or historical example to use as an example.