There is no one answer about what is competitive advantage or one way to measure it, and for the right reason. Nearly everything can be considered as competitive edge, e.g. higher profit margin, greater return on assets, valuable resource such as brand reputation or unique competence in producing jet engines. Every company must have at least one advantage to successfully compete in the market. If a company can't identify one or just doesn't possess it, competitors soon outperform it and force the business to leave the market.
So imagine that you have a company, then answer this question "How can we measuring competitive advantage?"
note: the answer only one page using your own word without write references.