Edison Schools work on the principle of being partners with the school district concerned. They are divided into three sub-companies: District Partners, Charter, and Alliance. In addition Edison runs afterschool programmes under the Newton brand and extended school year programmes under the Tungsten brand.
Edison has also made some headway in Britain with Edison Schools UK. Colbayns High School in Essex was the first Edison School in that country, and received praise from OFSTED for its progress over nine months.
Edison Schools bases its approach on ten fundamentals and various core values. The fundamentals include a better use of time (which means a longer school day and a longer school year—198 days as opposed to 180 in the standard American school) and assessments that provide accountability (including benchmark assessments and a structured portfolio and a quarterly learning contract).
Edison's stock was publicly traded on the NASDAQ for four years. The company reported only one profitable quarter while it was publicly traded. After reaching a high of close to USD$40 per share in early 2001, shares fell to 14 cents. Also in 2001, the Securities and Exchange Commission charged that Edison failed to disclose that as much as 41 percent of its revenue that year consisted of money that it never saw: $154 million. By 2002, Edison was courting Roger Milliken for a possible bailout. The company was eventually taken private in 2003, in a buyout facilitated by Leeds Weld and Liberty Partners on behalf of the Florida Retirement System, which handles pension investments for the state's public school teachers; The deal valued the company at $180 million or $1.76 per share. The three pension fund trustees at the time that endorsed the deal were: Florida Attorney General Charlie Crist, Florida Chief Financial Officer Tom Gallagher, and Florida Governor Jeb Bush.
After losing many contracts, Edison diversified away from the management of public schools and into marketing conventional supplemental services such as testing, summer school and tutoring. Most of its new business involves providing such services rather than trying to manage schools.
In 2008, the School District of Philadelphia, Edison's largest single client with 20 schools (Edison was originally planned to take over the entire district), later announced plans to dismiss the company as a manager, noting that it and other private firms would be eligible to reapply. By June 18 that year, Philadelphia's School Reform Commission voted to seize six schools from outside contractors— four of them run by Edison— citing lack of improvement.
Edison's educational and financial performance has been the subject of criticism. Despite initial promises of costs reductions client districts reported higher costs for their Edison schools. Edison's claims about academic improvement failed to live up to the company's promises. A July 2002 New York Times analysis of Edison's claims found that the troubled Cleveland, Ohio, school system achieved higher gains than Edison's schools when analyzed with the methodology Edison applied to its own schools' achievement.
Edison's methods and processes were mentioned prominently in Alyssa Quart's Branded: The Buying and Selling of Teenagers (2003), when some students started a demonstration against an Edison School being built in their area, due to the commercial takeover of their public schools.
Kenneth J. Saltman's The Edison Schools: Corporate Schooling and the Assault on Public Education (Routledge, 2005) examines the efficacy of the company and raises questions about the broader social, political, and cultural implications of public schools being run for profit.
In the period the failure of Edison Schools to revolutionize education became apparent, supporters of privatised education have criticised Whittle's for entering contracts with public school districts rather than setting up completely private schools. Writing in the Wall Street Journal in 2005, James K. Glassman stated