As people are called to transform data, information and past experiences in
to effective knowledge, the management of individual competencies will beco
me more and more important in knowledge-based firms. This paper presents bo
th theoretical and practical aspects concerning the management of competenc
ies, based on a seven year field research conducted in a large R&D firm. Th
e main conclusions of the research are: 1) competencies are constructed by
organizational members who internee through natural language; 2) it is impo
ssible to separate the act of competencies' identification from the act of
evaluation; 3) relevant competencies emerge from explanation discourses del
ivered by observers in the attempt to justify their judgement about the per
formance of an individual within given situations; (4) it is possible, by m
eans of fuzzy logic, to design evaluation support systems (ESS) of competen
cies by analysing explanation discourses. These assumptions are particularl
y suitable for organizations operating in a turbulent context, where compet
encies frequently change.