One of the links goes to a chart from the study author that ranks interventions by estimated effect size: http://visible-learning.org/hattie-ranking-influences-effect...

There's a definition of some of the terms here: http://visible-learning.org/glossary/

Its a list of what doesn't work and recommendations to counter them. It is giving options for what can work, but isn't practiced enough to be certain of.

Also, circumstances are different everywhere, so you can't just solve everything with an easy answer.

It's more of a hyperbole for food for thought and to kick-start discussion.