I have always believed good teaching matter.  I believe teacher quality is the single greatest predictor of school effectiveness.  Of course, when I say "school effectiveness" I mean what a school does to promote learning and healthy development.  (So, a school that has high student achievement simply because it happens to be in a high income neighborhood does not warrant brownie points.)  No matter what else you do, in the end, it is the daily interactions between teachers and students that make-up the educational experiences. 

The educational experience is made up of a variety of other factors that either help the teacher perform better (e.g., good curriculum, ample materials, small class sizes, safe schools, adequate learning time) or worse (poor curriculum, limited materials, large class sizes, unsafe schools, truncated learning time). 

Other factors are simply not within the realm of the school and therefore should not be mixed up with the school quality debate.  Things like poverty, school size, parent involvement and other contextual factors matter, of course, and poverty is highly predictive or student performance.  Yet, we tend to mush everything together and forget that there are many things under the control of teachers that can be done effectively and when done well, will have a notable positive long term impact of the lives of students.

The new study is further testimony to this.