Here are three popular statements about teacher quality. Would you say they are fact or fiction?

1. The quality of an education system cannot exceed the quality of its teachers. 
2. The most important single factor in improving quality of education is teachers. 
3. If any children had three or four great teachers in a row, they would soar academically, regardless of their racial or economic background, while those who have a sequence of weak teachers will fall further and further behind.

If you are convinced that these are true, then I would ask that you read Pasi Sahlberg's post "What if Finland's great teachers taught in U.S schools?"

The best education systems understand that school culture matters more than teacher quality. 

No school or school system has ever become great without great teachers, but what can an excellent teacher do about a child who needs glasses, has cavities or is hungry? To say that teacher or school quality is the most important variable in education is at best naive. Education historian Diane Ravitch writes, "Reformers tell us that teachers are the most important influence within the school on student scores, and that is right. But the teacher contribution to scores is dwarfed by the influence of family and other out-of-school factors."

Ultimately, great teachers make great schools, but great teachers can't do it alone – they require the support of an equitable society. If we are not careful, we risk misinterpreting the scores, and instead of waging war on poverty and inequity, we end up waging war on teachers and schools.