Volume 9 of 10 in the Engineering-to-Research Monograph Series. Applied computing and cybersecurity research has a methods problem that masquerades as a results problem: a model that performs well on one dataset or a defense evaluated on one testbed is too often reported as a finding when it is at best a result awaiting validation. The visible symptom is the documented reproducibility crisis; the underlying cause is insufficient research-methods rigor. This monograph synthesizes three strands of formal research training, namely quantitative statistics, research design, and qualitative inquiry, into a coherent mixed-methods, reproducibility-first framework, and argues that socio-technical problems require statistical validity to establish whether an effect is real, qualitative inquiry to establish why and for whom, design discipline to make the question answerable, and reproducibility practices to make the answer trustworthy. Grounded in regression and logistic modeling, a doctoral research-design study, and a full qualitative interview study with thematic analysis, it contributes an integrated research-methods framework, two methodological design principles, and a validation standard for the series and the author's forthcoming dissertation.The paper and figures are licensed CC BY 4.0. This work contains no confidential or proprietary employer information.