"Great by Choice" distinguishes itself from Collins's prior work by its focus not just on performance, but also on the type of unstable environments faced by leaders today. With a team of more than twenty researchers, Collins and Hansen studied companies that rose to greatness--beating their industry indexes by a minimum of ten times over fifteen years--in environments characterized by big forces and rapid shifts that leaders could not predict or control. The research team then contrasted these "10X companies" to a carefully selected set of comparison companies that failed to achieve greatness in similarly extreme environments.