Box 18.1.a: Potential benefits of IPD

IPD may be beneficial in the following situations.

  •  Many studies are unpublished or published only in the grey literature.

  • There is poor reporting of studies (e.g. information presented is inadequate, selective or ambiguous).

  • A high proportion of individuals has been excluded from published analyses.

  •  Obtaining additional longer-term outcome data beyond that reported may provide useful insights (e.g. for mortality or child development outcomes).

  • Outcome measures have been defined differently across studies.

  •  Time-to-event outcome measures are required.

  • Multivariate or other complex analyses are required.

  •  Exploration of interactions between interventions and patient-level characteristics is important.