Mary Michon studied the routine of 6th grade from the back of classrooms for months, to see how children treat one another and think of adults. She visited urban and rural schools; met with parents and teachers. Michon used all her observations to create the fictional Timotheusschool, a primary school set somewhere in the Netherlands. Everything in the series is based on real events. Several of the 23 children who played the students were discovered during her research. Rehearsals were held every Saturday for a year, and filming was done during school holidays. Some topics like emancipation and the debate over sex education are typical of the early 80s, but friendship, divorced parents, or the Cito test - are timeless. Mylou Frencken (who played Marja), Barbara Pouwels (who played Ellen) and others from the show became professional actors. Sports presenter Jan Joost van Gangelen, was the toddler who played Jannie's younger brother.