... specific processes that must be personally adapted to each learning task.” It’s about setting goals, selecting strategies to attain those goals, monitoring progress, restructuring if the goals ... variable in the study referring to the manner and approach of providing direction, implementing plans, and motivating people (Lewin, 1939; Clark, 2010). Motivation in diversity in this study, it refers ... affecting the performance of high schools at Hai Phong City in Vietnam. Objectives of the Study This study determined the principals’ leadership styles and instructional variables affecting...