Develop a comprehensive mixed methods research design for investigating a complex social phenomenon (such as organizational change, technology adoption, or public health intervention). Your design should include: theoretical framework, research questions, sampling strategies for both qualitative and quantitative components, specific data collection methods, integration points between methods, analysis approaches for each component, and meta-inference techniques. Explain the rationale for your design choices based on methodological literature. Discuss validation strategies, credibility enhancement techniques, and potential limitations of your approach. Include a detailed timeline and resource allocation plan.