intermediate level and a performance-based group at advanced level. The requirements of the performance-based group at advanced level are the most demanding and this school type generally prepares pupils for transfer to the matura schools. Cooperative model The cooperative model is based on core classes with different performance requirements. Each pupil is assigned to a core class according to his or her performance level. The pupils attend lessons in certain subjects in differentiated requirement-based groups (whereby the core classes are mixed). Integrated model The integrated model does not use different school types or core classes. Pupils with different performance levels attend the same class and mixing is maintained. In certain subjects, teaching occurs on differentiated requirement-based levels. International education As of January 2015, the International Schools Consultancy (ISC) listed Switzerland as having 105 international schools. ISC defines an 'international school' in the following terms "ISC includes an international school if the school delivers a curriculum to any combination of pre-school, primary or secondary students, wholly or partly in English outside an English-speaking country, or if a school in a country where English is one of the official languages, offers an English-medium curriculum other than the country’s national curriculum and is international in its orientation." This definition is used by publications including The Economist. Switzerland was the birthplace of the International Baccalaureate in 1968 and 50 schools in Switzerland offer one or more of the IB programmes (Primary, Middle Years, Diploma and Career-related Programmes). Tertiary Tertiary education depends on the education chosen in secondary education. For students with a matura, university is the most common one. Apprentices who attended a vocational high school will often add a Fachhochschule or a Höhere Fachschule to their curriculum. There are 14 public and generic universities in Switzerland, 10 of which are maintained at cantonal level and usually offer a range of non-technical subjects. Of the remaining 4 institutions, 2 are run by the Swiss Confederation and are known as "Swiss Federal Institutes of Technology". Switzerland is well known for its advanced business education system. A number of world-class universities and MBA programmes, such as the International Institute for Management Development, HEC Lausanne, University of St. Gallen, Kalaidos FH and University of Zurich belong to that category. All of them are also registered in the Financial Times ranking. See also the list of universities in Switzerland. Switzerland has a high rate of international students. In