The dynamic model of educational effectiveness refers to eight factors that describe teachers' instructional role. A multidimensional framework for measuring both quantitative and qualitative characteristics of teaching factors is also proposed. Empirical support for the validity of the model has been provided, which revealed that the teaching factors can be grouped into five stages situated in developmental order. In this study, for the first time, a qualitative methodology is used to provide an in-depth analysis of three video-lessons through the perspective of the five stages of effective teaching. Thus, we present how each stage is defined and use the cases of the three video-lessons to justify the rationale for these stages and help readers see how observational data are used to identify individual improvement priorities and provide differentiated feedback, even to teachers allocated to the same stage. Finally, based on the qualitative analysis of the three case-studies, strengths and limitations of the dynamic model to evaluate quality of teaching for formative reasons are identified.