We know from many other studies that local knowledge, even anecdotal knowledge can make a valuable contribution to knowledge production and decision making. Here is a related story on the Sunday Telegraph:
In its most recent report, it stated that observed reductions in mountain ice in the Andes, Alps and Africa was being caused by global warming, citing two papers as the source of the information.The IPCC report (AR4, WG 2) has a table that lists the two sources here.(Schwörer, 1997; Bowen, 2002 are the disputed sources)
However, it can be revealed that one of the sources quoted was a feature article published in a popular magazine for climbers which was based on anecdotal evidence from mountaineers about the changes they were witnessing on the mountainsides around them.
The other was a dissertation written by a geography student, studying for the equivalent of a master's degree, at the University of Berne in Switzerland that quoted interviews with mountain guides in the Alps.
The revelations, uncovered by The Sunday Telegraph, have raised fresh questions about the quality of the information contained in the report, which was published in 2007.
Is this bad practice just because it relies on non-scientific sources? How is 'propoer' data collected? What is the difference between them? Why is one better than the other?