by the Referendariat (training on-the-job), which normally lasts for 18–24 months. During this time, the student teacher gains practical teaching experience under the supervision of experienced colleagues. This phase is completed by the "Zweites Staatsexamen," which assesses the trainees' practical teaching ability. Those having successfully completed both the first and second state examinations may then apply for a position at a Gymnasium or lesser schools. However, the systems of teacher education differ among the Bundesländer, include exceptions and are often modified. One trend is the abolishing of the first state examination in favour of Master of Education programmes. The second state examination is not affected by this development. Admission to a gymnasium Admission procedures vary by state and gymnasium. Most gymnasia do not have written entrance exams. In some cases, students need a certain grade point average in order to apply to gymnasium. In most cases, students applying to a gymnasium nominally need a letter of recommendation written by the primary school teacher. The letter covers the child's academic performance, classroom behaviour, personal attributes, leadership abilities and extracurricular activities. Based on that letter, the gymnasium determines the applicant's suitability for the school. Some gymnasia have informal interviews during which they present their school to the applicant and in turn, learn about him as the school representative works with the applicant and his parents to find out if that gymnasium is a good fit for the child. The state of Berlin allows its gymnasia to pick 65% to 70% of their students, the rest being selected by lottery. Any qualified child can enter the lottery, regardless of previous school performance (see: Education in Berlin). Some gymnasia are inundated with applications and some children have to resort to second or third choices. Tuition State-funded schools (a big majority) are tuition-free, as foreseen by the respective laws, even often on constitutional level. Segregation of students by parent wealth or income is looked down upon, to the point of being an exception to the constitutionally guaranteed freedom to have private schools (Article 7 section 4 of the German constitution, Sondierungsverbot). Of the private gymnasia, the vast majority is run by the Catholic Church on very low tuition fees (which is more easy as by Concordat, the Church receives a high percentage of the amount of money the State need not spend for a pupil in a Church-school); fees for schools who need to earn