Based on studies in learning psychology, biology and education, the original technique "Lernen durch Lehren" ("LdL)" (German for "learning by teaching") has been elaborated into a meta-model ("Meta") "LdL" that aims at giving students a platform to acquire the competencies considered necessary for knowledge societies. Ninety-seven former students of university classes modelled on ("Meta") "LdL" participated in a questionnaire to determine the effectiveness and efficiency of ("Meta") "LdL." A majority of participants attested "LdL" to have allowed for a gain in all competencies and claimed that no other method they were aware of would be more efficient than "LdL." (Contains 3 tables.)