Different learning methods (online, blended, blended-online and face-to-face) have been examined widely since the late 1990s. Although many design studies discuss engagement with these new methods in relation to studio modules, research/theory modules have not been investigated yet for interior architecture with both qualitative and quantitative data as a holistic approach. This study reveals how the new blended online learning method and the COVID-19 pandemic affected students’ written outcomes in a research/theory module that accompanied their design module. For this purpose, the final written submissions of two year groups (2019–2020 vs. 2020–2021) are compared with both qualitative and quantitative analyses: their grades (performance), image (visual productivity) and reference (engagement with research) numbers and NVivo word count analyses (semantic analyses). The results show no significant difference between these two groups for both qualitative and quantitative analyses. Moreover, the study reveals that the numbers of images and references are good predictors for the grades of final-year students, thus showing their contribution to overall performance. Final-year research/theory modules in interior architecture might therefore be taught with blended online learning methods and can challenge, innovate and tailor studio teaching to contemporary needs. The study findings will be beneficial for educators and professionals, as well as managers, institution administrators, policymakers and decision-holders in HE who aim to employ blended online learning.