https://phys.org/news/2018-07-quality-evidence.html

Every year, millions of dollars are invested in the professional development of teachers in schools in every state and territory, in addition to the professional development investments made by schools, local communities and teachers themselves.

The teacher professional development industry in Australia is thriving with an abundance of expensive courses, events and gurus offering advice or endorsing products, with little evidence (or evidence of limited quality) that any of it improves teaching.