Do We Know How to Help Teachers Improve?

A school district in the United States spends annually about 90 to 160 million dollars, or about $10,000 to $19,000 per teacher, for professional development. A large piece of this investment comes from salaries of people who provide instructional support (coaches, instructional and curriculum specialists, professional learning community (PLC) leaders, teacher evaluation staff) and the time spent by the teacher on these programs. A study recently released by The New Teacher Project (TNTP) finds that these programs have no measurable positive results to show. Beth Braverman briefly discusses this report in an article in The Fiscal Times with a multi-billion dollar question:

Why We’re Wasting Billions on Teacher Development

Clarifying the findings, the TNTP report states:
To be clear, an outsized investment in teacher support is not necessarily unwise or unmerited; after all, if teacher improvement were achieved at scale, it would have an enormous effect on students. The problem is our indifference to its impact—that all this help doesn’t appear to be helping all that much. 
In fact, the study finds some instances where professional development seems to have an effect on teachers but in this case, the amount spent for these programs is even higher, $33,000 per teacher per year. The study cannot decipher specific programs that work, but still manages to draw several recommendations. There is one recommendation provided, in my opinion, that appears quite promising:

Above copied from
The Mirage: Confronting the Hard Truth
About Our Quest for Teacher Development
The reason why I regard the above as promising is its similarity to the approaches described in a previous post in this blog, "An Excellent Teacher for Every Student".

In any case, the study should help us realize that helping teachers become more effective is a huge undertaking that requires a sizeable investment. This therefore indicates how truly expensive it is to modify a curriculum. A complete overhaul of basic education obviously comes with a huge cost and not acknowledging how much it really takes to do so simply ensures failure.