Abstract
Research in organizational psychology and leadership uses different methods, yet the reasons for selecting one approach over another are often presented as preferences rather than as design fit. This paper aims to clarify when a mono-method design is adequate, when a multi-method design is needed, and when a mixed-methods design is worth the added cost and complexity. This paper applies a qualitative method that combines (1) a brief conceptual framing of quantitative and qualitative paradigms and (2) a structured review of a purposive sample of leadership and organizational psychology studies (between 2011 and 2026), selected to represent quantitative, qualitative, and mixed-methods designs. Quantitative designs provide breadth and comparability but can underplay context, culture, and causal pathways. Qualitative designs provide depth and meaningful reasoning but face limits in scale, time, and transferability. Mixed-methods designs can bridge these gaps through integration, but integration itself becomes a risk caused by dominance of one method, weak linking logic, or high resource needs. The paper offers a simple method-fit logic and a practical set of criteria that can be used early in study planning to align the research question, context, and constraints with an adequate design choice. No single approach is always adequate, but not every problem needs mixed methods. Adequacy depends on the question, the context, the maturity of the construct, and the constraints.