comparative cross-system theory educational effectiveness interconnection of teaching and learning sustained learning opportunities sustained learning opportunities for students teaching and educating teachers teaching theory the artistry of teaching thema EDItEUR::J Society and Social Sciences::JN Education thema EDItEUR::J Society and Social Sciences::JN Education::JNC Educational psychology thema EDItEUR::J Society and Social Sciences::JN Education::JNM Higher education, tertiary education::JNMT Teacher training theories for student learning theorizing teaching