Oral histories and life stories, as specific “documents of life” (K. Plummer) and narrative forms, have hybrid genre structure, a particular relation to reality, and the process of their evaluation poses different methodological questions. The use of oral histories and life stories as resources and evidence is especially complex issue. These texts are subjective with regard to reconstruction of memories and construction of narratives, as well as intersubjective and dialogical, considering that they are created collaboratively by the interviewee and the interviewer, starting from the conceptualisation of the interview up to its interpretation. The paper discusses the criteria for validity and reliability in oral histories and life stories, which concern advantages and limitations of a field interview (i.e. oral history and life story method), and aspects of constructing narrative identity in oral history and life story interview. The interview is considered to be a form of a heuristic collaboration between interviewer and interviewee, with their shared authority in a dialogue. However, there can be certain methodological limitations regarding, for example, conduction of an interview, relation between participants in a research, interpretation of data, influence of a particular context, employment of specific narrative or linguistic conventions in the construction of narration, and they may affect evaluation. In the final section the importance and forms of evaluation in narrating is discussed. Relaying on sociolinguistic and narrative analysis studies, some characteristic evaluating techniques in narratives are outlined, and also the way how evaluation is connected with other components of the content and the structure of a narrative. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 178010: Jezik, folklor i migracije na Balkanu]