EN
The purpose of this study is to show the effectiveness of the AA “4C” model in increasing teachers’ abilities. The study is a Single Case Research using the ABABA design. The subject of the study was a natural-science teacher. Results of the observation conducted continuously by three observers show that each of the teacher’s ability items improves from the first condition, to the second condition, and to the third condition. This finding is supported by the results of the Manova technique showing that the AA “4C” model is shown to be effective in improving teachers’ abilities in conducting authentic assessment.