A theoretical framework is the incorporation of theory into a research design. Theory can inform research questions, design models, and the interpretation of results, and thus can provide justification for the study and improve its validity.
Citation: Lederman, N. G., & Lederman, J. S. (2015). What is a theoretical framework? A practical answer. Journal of Science Teacher Education, 26(7), 593–597. https://doi.org/10.1007/s10972-015-9443-2