Complex sentence: Research during the sixties and seventies showed that the earlier children received Special Education, the better their outcomes; it also showed that families who were supported earlier were more empowered to advocate for their child later on (Guralnik, 1997).
Split into simpler sentences: Research during the 1960s and 1970s showed that the earlier children received special education, the better their outcomes. Research also showed that families who were supported earlier were more empowered to advocate for their child later on (Guralnik, 1997).