Jerry Ratcliffe
Evidence hierarchy
Updated: Aug 23, 2019
After a course assignment in my evidence-based policing class, it was clear that a few of my students were still struggling with the concepts around research evidence having a hierarchy of validity for policy makers. They comprehended the table here to some degree, but still struggled with some of the ideas.
Therefore here is the table, and a short video that I made to try and help them.

There is a related blog post that explains more here.
The video is below.
(This post was updated 23 August 2019 with revised link to related blog post and addition of the video)