Sesame Street was the first children's television program that used a curriculum with clear and measurable outcomes,[1] and was the first to use research in the creation of the show's design and content.[68] Research in Sesame Street had three functions: to test if the show was appealing to children, to discover what could be done to make the show more appealing, and to report to the public and the investors what impact the show had on its young viewers. Ten to fifteen percent of the show's initial budget of $8 million was devoted to research,[69] and researchers were always present in the studio during the show's filming.[16] A "Writer's Notebook" was developed to assist writers and producers in translating the research and production goals into televised material;[68] this connected the show's curriculum goals and its script development.[70] The Muppet characters were created to fill specific curriculum needs: Oscar the Grouch, for example, was designed to teach children about their positive and negative emotions.[71] Lesser called the collaboration between researchers and producers, as well as the idea of using television as an educational tool, the "CTW model".[72] Cooney agreed, commenting, "From the beginning, we—the planners of the project—designed the show as an experimental research project with educational advisers, researchers, and television producers collaborating as equal partners".[5]