Assessing and demonstrating data saturation in qualitative inquiry supporting patient-reported outcomes research

Abstract

In the patient-reported outcomes (PROs) field, strict regulatory requirements must be met for qualitative research that contributes to labeling claims for medicinal products. These requirements not only emphasize the importance of reaching saturation but also of providing documentary evidence that saturation has been reached. This paper reviews qualitative literature for useful definitions of the concept and for practical approaches for assessing saturation. The paper considers approaches in light of the rigorous regulatory requirements for PRO research that are used to support labeling claims for medicinal products and the wider requirements for flexibility and creativity in qualitative research in general. This assessment is facilitated by the use of examples from our past qualitative PRO studies. Based on conclusions from this assessment, we offer preliminary recommendations for future qualitative PRO studies for assessing and documenting saturation.

Keywords::

• guidelines
• methods
• patient-reported outcomes
• qualitative research
• quality of life
• saturation

Acknowledgements

The authors wish to thank the Ferring International Centre and Pfizer for the provision of data to enable this manuscript to be prepared. Specific thanks to Sandy K Nielsen (Ferring International Centre) and Katja Rudell (Pfizer). Thanks also to Emuella Flood and Andrew Lloyd for their comments on earlier drafts of the manuscript, to Paul Swinburn, Nuz Quadri and Katy Gallop for their assistance in identifying suitable examples from our PRO studies, and to Tamzin Furtado for assisting in making revisions in response to reviewers’ comments.

Financial & competing interests disclosure

All authors were employed by Oxford Outcomes Ltd during the preparation of this manuscript and at the time of publication. The studies which generated example data referred to in this manuscript were funded by Ferring International Centre and Pfizer. The manuscript was developed independently by the authors without any specific funding. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.