Jessica Guynn Workers' wages -- particularly those of low-income workers -- also get a small boost in enterprise zones, a recent study by University of Southern California professor Raphael Bostic and Franchise Tax Board economist Allen Prohofsky found. But the researchers could not establish whether the jobs or income gains lasted longer than the five years during which companies can collect the hiring credits. But other research studies dispute that enterprise zones are good for anyone but businesses. A 2003 report from the nonpartisan Legislative Analyst's Office concluded that enterprise zone incentives increase economic activity within small areas, but are "very costly" and have "little if any impact on the creation of new economic activity or employment."