Scott Shane is an academic that has studied franchising for several decades.
Shane is a professor of economics and entrepreneurship at the Weatherhead School of Management at Case Western Reserve University, Cleveland, Ohio
Please note this quote from his 2005 book.
Of the vast numbers of companies that begin to franchise every year, only a few are very successful.
Most of the entrepreneurs and managers who establish new franchise systems – more than 75 percent over 10 years and 85 perdnet over 17 years – end up with failed ventures and little financial returns to show for all of their effort.
Dr. Scott A. Shane, From Ice Cream to the Internet: Using Franchising to Drive the Growth and Profits of your Company