The advantages of employing a red team are several, but generally the most important one is providing a shift in perspective. Too often, whether it is when putting together a new budget, selecting a software application, building out a data center, or making a multitude of other decisions, we tend to fall into ingrained ways of thinking and deciding. This is especially true in organizations, where we can fall into that organizational mindset or are highly dependent upon standard operating procedures. A good red team can step outside that mindset and bring a different perspective to a plan, system, or security process that can often get overlooked.
A simple article that describes what a red team is. Easy read.