Selecting fit-for-purpose Clinical Outcome Assessments (COAs) using the ePROVIDE databases
Introduction
Clinical outcome assessments (COAs) are tools to capture how patients feel, function, or survive. COAs are available in a variety of formats to reflect different perspectives including Patient-Reported Outcomes (PROs), Observer-Reported Outcomes (ObsROs), Clinician-Reported Outcomes (ClinROs), and Performance Outcomes (PerfOs).
These COAs are considered ‘active’ COAs since the participant is ‘actively’ and intentionally completing the assessment. Passive COAs are also available and may be used to passively monitor a participant’s real-world activity through digital health technology (DHT).
COAs are increasingly important measures used within clinical research and practice to inform healthcare decision-making related to drug approval, reimbursement, and treatment plans. This prominence is evident from the rising number of guidelines published by the US Food and Drug Administration (FDA) and European Medicines Agency (EMA) which include COA recommendations over the past 25 years.
The 21st century has also seen an explosion in COA development. This presents opportunities to select COAs that have been rigorously developed and show validity evidence in specific populations and contexts measuring well-defined and patient-relevant concepts. However, this abundance of choice also engenders challenges in selecting COAs that are truly fit-for-purpose.
What is a ‘fit-for-purpose’ COA?
“First, validity is not an off/on, yes/no designation. No test is ‘‘valid’’ or ‘‘not valid.’’ Instead, validity comes in ‘‘degrees.’’ Second, validity is not a property of a test; rather, validity speaks to how a score from a test is interpreted or used” (Edwards et al., 2018)
Fit-for-purpose as a concept for health outcomes is situated within broader notions of validity. The FDA-National Institutes of Health glossary defines ‘fit-for-purpose’ as “a conclusion that the level of validation associated with a biomarker or COA is sufficient to support its proposed use” (FDA-NIH, 2016).
This definition is closely related to modern validity theory whereby the understanding of validity (and therefore what is fit-for-purpose) is centred around “sufficiency of evidence” (Weinfurt, 2025) for score interpretation. This evidence incorporates three essential components according to FDA thinking:
- A clearly defined concept of interest to measure within a specific context of use.
- A clear rationale as to why this COA is suitable for this concept of interest and context of use.
- Sufficient evidence to support the rationale (see figure 1 for the FDA overview).
ACOA could thereforebe fit-for-purpose for measuring symptoms in one specific population but unfit-for-purpose in a different population since “validity is not a property of a test” (Edwards et al., 2018). Current thinking on what makes a COA fit-for-purpose is therefore founded on assessing the concept of interest, the type of population, and context of use with which validity-related evidence was generated.
How to identify ‘fit-for-purpose’ COAs?
Deciding on whether a COA is fit-for-purpose entails rigorous evaluation of available evidence supporting its use to measure a specific and meaningful concept of interest in a well-defined population and context. Targeted literature reviews examine this evidence in the population of development and validation as well as regulatory opinions on the COA seen through drug label claims or guidelines on COA use. The ePROVIDETM databases are a centralized platform to assist users develop an endpoint strategy:
- PROINSIGHTTM can be used to review over 300 regulatory guidelines on what COAs are recommended for use in different populations and which concepts to measure with these COAs.
- PROLABELSTM provides an overview of which COAs have been used to measure which concepts for different populations in over 2000 product (drug/device) label claims. Once a researcher has an idea about the concepts they are interested in measuring for a specific population and context of use, this information can be cross-referenced in PROQOLIDTM.
- PROQOLIDTM contains over 8000 detailed COA descriptions to help contextualise how the COA is used in practice. This includes licensing, translations, recall period, scoring information etc. as well as understanding whether there is sufficient evidence to support the COAs use to measure the concept of interest in the specific population and context.
Using database-specific filters accelerates the identification of fit-for-purpose COAs which are specific to the needs of studies and patients. In table 1, elements that are key to consider when searching for a fit-for-purpose COA have been mapped to the PROQOLIDTM filters (along with an example) to demonstrate how this resource can be used to narrow down the vast number of available COAs. It is important to note that not all filters must be deployed when searching for a fit-for-purpose COA and the search criteria should always be adapted to the concept being measured, population, and context of use.
| Table 1: Elements to consider for selecting a fit-for-purpose COA mapped to PROQOLIDTM | |||
| Elements to consider for selecting a fit-for-purpose COA |
PQ filters |
Comments |
Worked example |
| Population | Therapeutic indication | A specific disease, condition, or symptom | Breast neoplasms |
Therapeutic area | A group of related diseases and conditions | Neoplasms/ Skin and Connective Tissue Diseases | |
| Age category* | E.g. child, adolescent, adult, aged | Adult | |
| Context* | E.g. treatment type | Chemotherapy, Adjuvant (optional) | |
| Concept of interest | Concepts of interest* | E.g. HRQoL, physical/ psychological functioning | Patient satisfaction |
Domains* | E.g. Specific areas which contribute to the overall measurement of the concept of interest |
Any | |
| Context of use | Type of outcome assessment | E.g. PRO, ObsRO, ClinRO, PerfO | PRO |
| Modes of administration* | E.g. self-administered, clinician-rated, interview-administered | Self-administered | |
| Data collection mode* | E.g. e-version, paper and pen, telephone-administered | Paper and pen/e-version | |
| Types of devices | E.g. Smartphone, tablet, laptop | Any | |
| Languages* | E.g. any translations that the COA is available in | Any | |
*Filters available through a subscription to PROQOLIDTM, for more information see here.
Conclusion
Choosing a fit-for-purpose COA will never be a simple choice, as researchers want to ensure that the data being collected, interpreted and used to inform health-care related decisions is meaningful for patients and their health. Making a choice requires careful and rigorous assessment of available COAs and the evidence supporting their use for specific populations, concepts of interest, and contexts of use. Resources such as the ePROVIDETM databases can accelerate these evaluations by centralizing data on COAs and regulatory opinions in one place to facilitate comparison of concepts, populations, and validity-related evidence. Through synthesizing these data, researchers can make more informed decisions about which COAs are the most fit-for-purpose to measure concepts that are meaningful for their patients.
References:
American Psychological Association (2014) Standards for Educational and Psychological Testing. Washington, DC
Cella D, Nolla K, Peipert JD. “The challenge of using patient reported outcome measures in clinical practice: how do we get there?” J Patient Rep Outcomes. 2024 Mar 21;8(1):35
Food and Drug Administration (FDA). (2020) Clinical Outcome Assessment (COA): Frequently Asked Questions. Available at: https://www.fda.gov/about-fda/clinical-outcome-assessment-coa-frequently-asked-questions [Accessed on 18-06-2025].
Food and Drug Administration (FDA). (2022) “Patient-Focused Drug Development: Selecting, Developing, or Modifying Fit-for Purpose Clinical Outcome Assessments”. PFDD 3. Available at: https://www.fda.gov/media/159500/download [Accessed on 18-06-2025].
Food and Drug Administration (FDA). (No date) Patient-Focused Drug Development: Selecting, Developing, or Modifying Fit-for-Purpose Clinical Outcome Assessments. Available here. [Accessed on 16-06-2025].
FDA-NIH Biomarker Working Group. BEST (Biomarkers, EndpointS, and other Tools) Resource [Internet]. Silver Spring (MD): Food and Drug Administration (US); 2016-. Glossary. 2016 Jan 28 [Updated 2025 Jan 16]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK338448/ Co-published by National Institutes of Health (US), Bethesda (MD).
Edwards MC, Slagle A, Rubright JD, Wirth RJ. “Fit for purpose and modern validity theory in clinical outcomes assessment”. Qual Life Res. 2018 Jul;27(7):1711-1720
Makhni EC, Hennekes ME. “The Use of Patient-Reported Outcome Measures in Clinical Practice and Clinical Decision Making”. J Am Acad Orthop Surg. 2023 Oct 15;31(20):1059-1066
Oehrlein EM; US Food and Drug Administration Interviewees. “An Interview With the Food and Drug Administration About Draft Patient-Focused Drug Development Guidance 3: Selecting, Developing, or Modifying Fit-for-Purpose Clinical Outcome Assessments”. Value Health. 2023 Jun;26(6):791-795.
Weinfurt, K.P. (2025) “The Argument-Based Approach to Validity Applied to Clinical Outcome Assessments: Some History and Notable Features”. Value in Health, Volume 0, Issue 0.