Purpose: This paper seeks to explore how managing by objectives (MBO) has been adopted in Swedish schools and to reflect on some of the consequences in a longitudinal study. Results relate to whether introduction has increased student performance and whether it works as a tool for the principals to create more effective schools. Design/methodology/approach: A comparative cross-sectional study was made on the adoption of MBO as perceived by principals in upper secondary schools in Sweden. Initially, a mail questionnaire was distributed to every principal in Swedish upper secondary schools, which determined the extent to which mandated MBO practices were being implemented. Ten years later, the study was replicated, which made initial and subsequent practices comparable. Findings: Principals' perceptions suggest that the effects of MBO have diminished over the ten-year period. Ancillary measures of student performance correlated to MBO practices appeared statistically insignificant, or perhaps even negative. Thus, the change appears to have produced unimproved student performance, frustrated principals and perhaps somewhat less stressed teachers. Practical implications: These findings have implications on the direction the management of upper secondary schools subject to central direction may take. Although MBO may improve efficiency in staff performance, it appears to have little effect on effectiveness, if student performance is used as a criterion. Originality/value: Adoption measures of MBO have been obtained and associated with student performance for the first time. (Contains 4 tables, 1 figure and 3 notes.)