The paper presents a formative assessment method of the internal factors consisting of motivation and learning strategy of individual students. It enables educators to choose students to focus their supervision. The method considers the internal factors of students result in their learning behavior. The learning behavior is extracted from learning logs which are automatically taken from the e-learning sites to study programming. The internal factors of individual students are figured out through the decomposition of their learning behavior with the non-negative matrix factorization. For 48 students of C programming course of Ritsumeikan University, the method showed predicted active students who can solve difficulties by themselves. Consequently, the educators can focus their efforts on students needing cares in a timely fashion.