1. Literature search

1.2 Source documents

c. Searching for unpublished documents

This aspect must be considered. The results of research in medicine and in other scientific domains are most often published, yet unpublished data are not the exception.

The reason is that in the industry, the results of clinical research, whenever they are negative, do not create excitement. This goes for therapeutic trials as well as for molecular testing.

Yet negative data are nevertheless data. Also, some topics are politically sensitive.

And data, such as that generated from epidemiological studies that deal with contamination, modes of disease transmission, and methods of preventing the spread of infectious diseases, may not be available in real time. Even published data must sometimes be analyzed with the publisher’s biases taken into account!.

Unpublished results can be found in what is known as "grey literature". Prior knowledge of institutional and professional domains is required to successfully retrieve them.

Qualitatively speaking, such data may be significant, especially in the area of new technologies (e.g. studies in "technology assessment"). Industrial reports and preliminary clinical reviews on the development of new technologies for screening, diagnostics, and treatment, are not always readily available in their early stages.