CTW was headed by Joan Ganz Cooney. a television producer who. with Lloyd Morrisett of the Markle Foundation. attracted funding from federal and private sources, including the U.S . Department of Health. Education, and Welfare; the National Institutes of Mental Health; the Carnegie and Ford foundations: and the Corporation for Public Broadcasting. Sesame Street, designed to promote the intellectual and cultural growth of preschoolers (particularly disadvantaged preschoolers). revolutionized children's educational television when it premiered in 1969 and established the CTW model for program development and research regarding children and television.

     The "CTW model" refers to the unique process of educational program development at the workshop. The paradigm evolved under the direction of Cooney; Edward L. Palmer, director of research; and Gerald S. Lesser. chair of the CTW Board of Advisors. Each of the workshop's series begins with extensive initial planning sessions involving producers. researchers, content experts. and advise rs. The concepts developed in these sessions are then translated into program segments and pretested with the target audience. Frequently. The testing extends for lengthy periods prior to actual production so that producers can see how the audience reacts to the educational messages embedded in the programs.

     In preparing for Sesame Street, for example. the re­search and design focused on the demonstrable ability of the program's elements to attract  attention. appeal to the audience, and be comprehensible.Researchers assessed the attention-holding power of material by presenting content in competition with potential distractions. The tactics that elicited the most interactivity among viewers were explored further. The research concluded with tests to assess what appropriate audiences recalled about the programming. As a result of these procedures, Sesame Street went on air with very specific attention-holding tactics, such as fast movement. humor. slapstick. and animation. It was packaged in a magazine format and presented a carefully planned curriculum that focused on teaching letters and number skills.

     Program development at the workshop does not stop when programs are broadcast. In addition to the unusual attention to formative research. The CTW model also includes a strong commitment to summative research; as part of its summative research plan. the Educational Testing Service (ETS). was commissioned to evaluate Sesame Street. In a series of studies published by ETS in 1970 and 1972, researchers Ball and Bogatz found that viewing the program had a significant impact on test subjects and offered evidence of the development of a positive attitude toward school among those subjects. In a 1976 study. Cook and Connor discovered that parental encouragement was vital to learning and that advantaged families were more likely to watch Sesame Street, thus ironically arguing that the gap between that group and the disadvantaged was not narrowed by the availability of the program.

     Broadcast continuously in the United States since 1969. Sesame Street is clearly the workshop's outstanding success. From its beginning as a weekday show designed to teach thinking skills and factual knowledge such as letters and number skills. Sesame Street's curriculum has been broadened to include goals such as reasoning. bilingual skills. acceptance of special needs, ecology. and health. The program is viewed by almost half of all U.S. preschoolers on a weekly basis.

     Versions of Sesame Street have been broadcast in more than 40 countries. with more than 20 showing the national editions of the program in 2002. The international productions share the U.S. programs' commitment to teaching learning skills and values, such as tolerance and kindness. but are specially tailored for the children in the nation or region in which they are broadcast. For example, the Egyptian show emphasizes the educational needs of girls. and. in the 2002-03 season. The South African version included a Muppet child living with AIDS. The Israeli-Palestinian co production began in 1998 portrayed friendship and tolerance between Israeli and Palestinian Muppets and presented segments in both Hebrew and Arabic. However, by 2002, the co-production (which now included Jordan as well) had eliminated stories about Arabs and Israelis interacting and changed its name to Sesame Stories. The changes reflected the producers' conclusion that the heightened conflict between Israel and the Palestinian Authority made too unrealistic the notion of a street where the two groups would meet as peaceful neighbors.

     Following the success of Sesame Street , CTW went on to produce a number of other major educational programs, including The Electric Company, which premiered in 1971 and was in production for a decade. The Electric Company emphasized symbol and sound analysis and meaning in a half-hour program designed to help slower readers catch up and good readers reinforce their skills. The Electric Company used the CTW model, a magazine format, and a variety of entertaining and attention-grabbing production techniques. Formative research for the program included innovative eye-movement and eye-contact  measures of appeal and attention. ETS evaluation found  that The Electric Company fostered significant positive effects, particularly for the youngest target viewers. Feeling Good, a 24-episode experimental series, was programmed in 1974, designed to examine health issues and targeted particularly for young parents and low-income families. Funding difficulties and low ratings forced the program to be produced in stages with considerable format changes. Low public awareness of the program seemed to contribute to lack of demonstrable effects.

     3-2-1 Contact, a 65-program series for 8- to 12- year-old children, premiered in 1980 and focused on science and technology. The goals were to promote scientific thinking, participation in science activities, and awareness of science as a career, particularly for women and minority children. It used a magazine format with continuing features such as a mystery/adventure dramatic component. Research by Mielke and Chen in 1980 and 1983 found 3-2-1 Contact attractive to children, who responded particularly positively to the drama format used in the "Bloodhound Gang" segments.

     Square One 1V premiered in 1987 with the goal of increasing problem-solving ability and a positive attitude toward mathematics  among  8-  to  12-year-old children. Format features included Mathnet, game show parodies, and commercials. The program covered mathematical concepts from estimation through graphics, probabilities, and geometry. CTW research showed that viewers in the target age-group enjoyed improved problem-solving ability and more positive attitudes toward mathematics.

     Ghostwriter, a series focusing on writing skills, premiered in I 992. The series' appeal was built around a computer that provided  "ghostlike"  clues  that  enabled a group of young people to solve problems. Of these workshop programs, only Sesame Street is still in production, but because there is always a new audience of children available, most of the programs can still  be seen. These are only a sampling of the workshop's major projects. The workshop continues to produce many other television programs, including the recent animated series Dragon Tales and Sagwa,  both  intended for preschool viewers.

     By the 1980s, many of the funds for CTW were generated from Sesame Street product sales, the Sesame Place Amusement Park, and Sesame Street Live, a touring theatrical production. CTW became an unhappy participant in the struggles over Public Broadcasting Service (PBS) funding in the mid-1990s, when the financial success of Sesame Street was used as an example of why public funding was not needed to support educational children's programming. Despite such difficulties, the workshop-and Sesame Street in particular-remain a hallmark of children's  programming in the United States. In the early 21st century, Sesame Workshop continues to expand its efforts to educate and entertain children. Among other ventures, it presents an expansive website replete with interactive games for children, suggestions for crafts and other forms of creative play, advice for parents, features about members of the Sesame Street family and characters from other series, as well as information about the workshop, its mission, and its products. The workshop has also partnered with Nickelodeon to create a commercial-free, educational cable channel. Between 6:00 A. M. and 6:00 P.M., the channel is called Noggin and offers programming for preschool children; during the other 12 hours of the day, the channel is called The N and shows programs for older children and teens. Featuring new and classic programs produced by the workshop and by Nickelodeon, Noggin/The N reached 22 million households in 2001. Like Sesame Workshop, both Noggin and Then complement their TV offerings with interactive Internet sites.