Like many things, there's substantial evidence on both sides of the argument. The devil is usually in the details, and this is a case where success or failure seems to be greatly affected by the quality of the programs themselves and the people who administer them.
https://link.springer.com/article/10.1007/s12122-016-9229-0
https://academic.oup.com/aler/article-abstract/19/2/391/3066...
Like many things, there's substantial evidence on both sides of the argument. The devil is usually in the details, and this is a case where success or failure seems to be greatly affected by the quality of the programs themselves and the people who administer them.