Every research is based on three aspects: the special system of questions, the advanced hypothesis, and the manner of evaluation the attained results. All the phases have at disposal applied methods and theoretical essentials, to realize them. Empirical research is based on cognitive processes, which need a psychosocial analysis, directed to the researcher as well as to the person giving the asked information. Only in this case we are able to appreciate the reliability and 'objectivity' of the presented data, To fulfil these demands ethnomusicology use the most sophisticated and exact medial tools, much more exhaustive than any of ethnological and anthropological research or the humanities in general use. The same importance has the system of administration, the archival work and all the safeguarding procedures in order to preserve the documents and records for the future in irreducible quality. The mentioned aspects are analysed on hand of research activities of two personalities: Béla Bartók and Karol Plicka, concerning their methodology of fieldwork as well as the attained results. In general: to evaluate the results we have to have in mind objective and subjective aspects concerning the fieldwork process and its use.