In translation and interpreting studies (TIS), source text analysis has enormous potential (Nord 2005; De la Cova 2017; Szymyslik 2019). To identify complex elements in a text, with a view to their analysis and systemization, TIS resorts to abstract, notionally dense concepts which, while interesting, nevertheless need to be operationalised methodologically in an eminently qualitative, complex manner. Examples of such concepts include translation problem (Nord 1997/2001; De la Cova 2017; Hurtado 2017), difficulty (Dahl 2004; Dragsted 2004), and error (O’Brien 2012; Koby, Fields et al. 2014). Translation-orientated corpus studies tend to be quantitative (corpus-based or corpus-driven, according to Baker (2006)) or, more rarely, hybrid studies which make it possible to work at a computer-friendly level of text analysis. Complex constructs, however, require essentially qualitative corpus methodologies, which are less frequently used precisely because of their complexity. This paper analyses the objectivation of complex concepts from a Grounded Theory perspective as a means of subjecting them to systematic study. It also presents some examples of qualitative research using corpora and explores the research potential of different tools in this regard. The conclusions drawn focus on methodological transferability based on a qualitative approach to complex concepts, and on the methods best suited to such contexts, like Grounded Theory and bottom-up categorisation (Strauss and Corbin 1990; Robson 2002; Böhm 2000/2004; Silverman 2011; etc.).