Research on bilingualism and executive functions has primarily focused on the presence or absence of an advantage, based on group comparisons between monolinguals and bilinguals. This research rests on two assumptions: first, that participant groups are mutually exclusive, and second, that important statistical practices are upheld. These assumptions, however, are linked to participant-related characteristics and data diagnostic procedures, which are often underreported. Importantly, bilingualism is a dynamic experience, reflecting how individuals interact with their environment through different languages. This interactional experience is essential for grouping participants within studies, and for drawing comparisons across studies. This paper addresses why definitive claims based on between-group investigations of bilingualism and executive functions are insufficient, particularly when research contexts are not considered, and proposes future research directions for the field.