FAKT is a non-profit consultancy to which I am closely linked for almost 30 years now.
www.fakt-consult.de

In NGO-IDEAs, in three phases about 20 German and more than 50 organisations from Africa, Asia and Latin America cooperated in order to create instruments of impact assessment which put target groups into the centre of action. There are instruments where disadvantaged population groups set their own objectives (www.ngo-ideas.net/impact_toolbox), in which impact can be assessed through rapid retrospective assessment (www.ngo-ideas.net/tiny_tools), reports on experience (www.ngo-ideas.net/field_experiences) and a manual to build impact oriented monitoring systems (www.ngo-ideas.net/monitoring_self_effectiveness).
www.ngo-ideas.net

In a two-year study process, a five-person research consortium explored how developmental education has an effect on participants and how these effects can be assessed. The study was financed by the German ministry for development (BMZ). The book is available as a PDF document and is currently being translated into English.
www.wirkungsorientierung.net (German)