Introduction. This article addresses the problem of developing teacher competence in providing feedback that motivates students toward productive learning behaviors. The aim of the research is to identify the characteristics of feedback that most effectively influence the motivation of school students engaged in project-based/research activities. Materials and Methods. The research methodology is based on a combination of behavioral, systemic, and humanistic approaches to the design of feedback. Their integration within the framework of L.S. Vygotsky’s classical idea about the teacher’s role in helping children overcome the boundaries of the ‘zone of proximal development’ enabled teachers to achieve feedback literacy and, in its turn, to empower teachers to develop this competence independently. The experimental content involved an analysis of the practices of Russian teachers using feedback methods based on approval and encouragement within the context of formative assessment of students’ project and research work texts. The independent variable comprised two methods of providing feedback: the first of them emphasizes the students’ personal resources and the second one does not emphasize them. Dependent variables included: the final assessment of the work according to established criteria; the fact of editing and improving the draft and submitting the final draft. Results. Feedback focused on the work itself, without emphasis on personal effort, proved to be more effective (d = 1.40) than feedback oriented toward the student’s personal development and motivation (d = 0.58). The experiment also revealed that teachers tended to assign higher grades when, under the experimental conditions, they focused their attention on the student’s personal qualities. The main barrier identified during the study was the high labor intensity of both methods, noted by the teachers despite their recognition of each method’s pedagogical value. The data obtained by the authors on the comparative effectiveness of the methods and the barriers to their application constitute a basis for improving the standards of teacher education. The novelty of the research lies in establishing and verifying a hierarchy of feedback method effectiveness, which contributes to both assessment theory and motivation theory. Conclusions. The study revealed significant differences in how alternative methods of feedback (at different levels – formative and developmental) influence the productivity of school students’ learning behaviors and teachers’ attitudes toward the practice of providing feedback.