TABLE 1Advantages and Disadvantages of Individual Study Designs Discussed in This Paper

Streamlined trials
  • Population-based so potentially good external validity
  • Large populations searched
  • Only suitable subjects invited
  • Reflects normal care
  • Reduced cost
  • Self-selected “healthier” subjects sign up so external validity is not perfect
  • ~ 50% of practices do not participate
  • Few subjects accept
  • Become “observational” rapidly
  • Similar bureaucracy
Cluster randomised trials
  • Reduced bureaucracy
  • Large populations studied efficiently
  • Most patients participate
  • No individual patient consent
  • Inexpensive, efficient, & quick
  • Treatments prescribed
  • Record-linkage outcomes
  • Do not (usually) need a clinical trials authorisation
  • Only anonymous data retrieved
  • Reduced statistical power from cluster design
  • Opt-out patients may bias study
  • Requires practices to consent
  • Requires efficient electronic tracking of anonymous subjects
  • Only suitable for products with a marketing authorisation. May be criticised as “seeding studies”
  • End-point validation required
  • Not suitable for all health outcome studies
Prospective observational follow-up studies
  • Consented subjects
  • Patient-reported outcomes
  • Able to contact patients
  • Large cohorts & frequent e-mail contact
  • Patients self-selected & more likely to take part in other research
  • Observes normal care
  • Reduced data privacy issues
  • Outcomes need to be validated (via family doctor) and coded
  • Ease of capture of further data
  • IT and clinical support resource issues
  • May not be representative of the population
  • Not randomised
Internet-only randomised trials of drug therapy
  • Theoretically feasible
  • Inexpensive
  • Patient-driven recruitment
  • Recruited by targeted advertising (i.e. doctor surgeries)
  • Internet only
  • Less field-based manpower required
  • Single-centre studies
  • Must comply with clinical trials legislation
  • Data-quality assurance required
  • Require family doctor assent
  • Need to engage public in research agenda to maximize utility
  • Requires Internet access and IT-literate subjects
  • More IT and office-based clinical staff
  • Bureaucracy may still be significant

From: Appendix J, Discussion Paper: Novel Ways to Get Good Trial Data: The UK Experience

Cover of Envisioning a Transformed Clinical Trials Enterprise in the United States
Envisioning a Transformed Clinical Trials Enterprise in the United States: Establishing An Agenda for 2020: Workshop Summary.
Institute of Medicine (US).
Washington (DC): National Academies Press (US); 2012.
Copyright © 2012, National Academy of Sciences.

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