Thank you Casey, Carolyn and all.
As soon as I posted my first reply, I realized that this is exactly what we are looking for in TRE - evidence-based research (although the anecdotal research is very rich already from all over the world), and my understanding of research is zero. I am therefore grateful to have been caught in this thread, and am looking for suitable examples of Pre&Post Tests, as given here.
Thank you all and best wishes.
Raymond Lambert