Goetze and Neukäter (1995) characterise open education by 11 only added features. Using the paradigm of pair-comparison 158 teachers judged features according meanings for open education. Teachers knowing the concept prefer the features in different frequencies. There are two dimensions called directiveness of teachers and activity of pupils to describe the structure of features concerning the criteria of reasoning. Kind of knowledge about open education has an effect in detail on teacher's decision regarding to typical features. It's mostly visible on the directiveness of teachers. A specification of theoretical base in open education is given now. It has to investigate empirically and could be a base to characterise and evaluate several forms of open education. The structure founded could be helpful for teachers starting with open education.