Purpose: As the first of two papers addressing challenges in applying best evidence to physiotherapy practice, this paper highlights the role of qualitative research and challenges researchers face in producing sound evidence for practice.Summary of Key Points: The challenge of what constitutes acceptable evidence to inform evidence-based practice is addressed in this paper with critique of the current over-reliance on quantitative methodologies that excludes a substantial body of valuable qualitative evidence to support sound practice. The current trend of relying on questionnaires to obtain psychosocial data is challenged on the basis of limitations of research design. Challenges to researchers from the quantitative and qualitative worlds to break down the political barriers separating these two groups are put forward. Lastly, we consider challenges that clinicians face in maintaining best practice based on when evidence is still largely not available or is compromised by limitations to research design with respect to population homogeneity, diagnostic inclusion criteria, intervention details, outcome measures and critical appraisal tools. Conclusion: Quantitative research alone is insufficient to understand patients’ pain and disability experiences. Researchers are challenged to improve their reporting of research with greater detail provided regarding populations, therapeutic environment and interventions used if clinicians are to be able to apply research findings in practice