data is often existent, but you have to know where to look for it.
Sometimes it is also resonable, to complement field research with desk research.
Our project managers for desk research know very well, where they have to search for the
supplementary information. They have also the ability to evaluate the information in terms of relevance
and can form it into a comprehensible mode.
Interviews of experts are another very productive method, which is also an element of desk research.