Shortly after beginning Sesame Street, its creators developed the "CTW model": a system of planning, production, and evaluation which only emerged after the show's first season.[21][note 3] The CTW model involved the interaction between television producers and educators, the development of a curriculum for three- to five-year-old children, formative research to shape the program, and independent summative research into what viewers learned.[21][21] According to Cooney, "Without research, there would be no Sesame Street."[2]