In the current study I explore the relationship between epistemology and methodology through a reanalysis of production data on grammatical gender in additionallanguage Spanish that were analysed in Gudmestad et al. (2019). This reanalysis consists of a shift in the epistemology from the one adopted by Gudmestad et al., where gender marking, which occurs between nouns and both determiners and adjectives, is a unified linguistic phenomenon. In contrast, the assumption in the present investigation is that the acquisition of gender marking entails learning gender assignment and gender agreement, two different learning processes that are observable in language behaviour with determiners and adjectives, respectively. In order to reflect critically on the relationship between epistemology and methodology and specifically on its influence on the interpretation of learner data, I conduct a multi-step analysis that is guided by the differentiation between gender assignment, which can be observed on determiners, and gender agreement, which can be observed on adjectives. I also discuss how the interpretation of the findings can be impacted by the epistemology that guides the current study.