“…The gaining of knowledge through research participation was mentioned 16 times overall, [25,27,41,44,54,59,60,62,67,73,76,81,82,[86][87][88] ranked in the top three reasons four times, [44,59,67,88] and was given as the top reason in one paper to participate [44]. Knowledge was ranked fifth in Sub-Saharan Africa and Eastern Europe, in [20,32,36,69,78], and ranked sixth overall.…”