In recent literature on interethnic relations, the dynamics and flexibility of ethnic identities get much at’ention. The concept "situational ethnicity", characteristic for this approach. implies that ethnic identities are context dependent: Selfconcepts and attitudes towards other ethnic groups are not conceptualized as stable and enduring dispositions but as frames which may vary with: (i) the domain of social interaction with members of other ethnic groups. and (ii) the specific conversational context in which these repertoires or frames are verbalised. As a consequence. it is assumed that the belonging to a specific ethnic group is not always an important element In the frames of references to be used for the perception and evaluation of other people and/or to be verbalised in conversations. The same applies to the way different ethnic groups are distinguished and defined. The paper will focus on the question how to get valid information on the context dependency of ethnic identities. After a discussion of pro s and con s of different research methods for this research goal. the paper will mainly focus on possibilities and pitfalls of open interviewing. Special attention will be paid to problems in interpreting 6 interwiew protocols in theoretical meaningful terms. A main difficulty in this respect is due to the fact that the empirical variety in answering patterns is not only dependent on the type of social interaction which respondents have in mind but also on characteristics of the interview situation and the research design. A frame-analytic model is proposed on behalf of the analysis of frames as articulated in answering patterns and frames respondents use in defining the interaction with the interviewer. Special attention is paid to the possible relations between both types of frames. The research case in question concems open interviews with pupils of a secondary school. Frame analysis of these interviews shows the role of frames concerning general aims of the research in the answering behaviour of respondents. In analyzing the ways these frames are constructed. the possible effects of the research design are discussed. The results of the study gives rise to a critical view on the method of triangulation: Methodological virtues of triangulation are often overestimated and it seems worthwhile to pay more attention to the methodological risks of triangulation.