Abstract
Fundamental theoretical considerations about inclusion and exclusion (cf. Loos and Schäffer, 2013, p. 53) are outlined initially in the first section. In the second paragraph, the sample and the methodology for both the main study on school development processes and the meta-analysis on detecting associated side effects whilst implementing competence-oriented assessments concepts (COAC) are described. In the third section, the findings are presented and subsequently interpreted. The contribution is concluded with further considerations concerning the phenomenon of structural paradoxes.