This report argues that the most effective way to raise academic achievement is for teachers to become inquiring professionals with action-research and reflective-thinking skills. The report defines effectiveness and examines the views of various stakeholders about what qualities they value in school, arguing that effectiveness is a complex concept and only researchers can measure it correctly. Other stakeholders are concerned with different qualities and not with effectiveness. The paper argues that teacher effectiveness must be improved in order to help children achieve more. Teachers are distracted by pressures put on them by other stakeholders with different priorities. The report examines literature on school effectiveness stability and concludes that effectiveness is unstable. It discusses different ways to restore effectiveness and notes a lack of convincing evidence for the effectiveness of externally generated initiatives. The report argues that a significant element of efforts to restore and maintain effectiveness must be the evidence-based practices of inquiring school teachers and administrators. Interviews with 35 teachers who completed a program at Leeds Metropolitan University to teach them action-research skills found significant obstacles to the school improvement effort. The report describes individual initiatives to raise students achievement, which tend to restore or maintain effectiveness. It concludes that such measures are likely to please many stakeholders whose priorities are not effectiveness. Interim recommendations for school improvement are included. Contains 49 references. (SM)