Conclusion
We have demonstrated that a checklist of the eight criteria of usefulness can be used successfully to explore the usefulness of clinical research. Focusing on preterm birth research, our usefulness assessment points out that those clinical trials so far lacked many usefulness features, with one tenth of trials meeting half of the items evaluated. Use of informative outcomes, patient centeredness, pragmatism and transparency should be key targets for future research planning. These usefulness criteria can be adopted across diverse domains of clinical investigations and may offer feedback to different stakeholders (researchers, patients, peer reviewers, journal editors, guideline developers and policy makers) to improve future study design.