This is an archived version of the Handbook. For the current version, please go to

Box 5.4.a: Factors to consider when developing criteria for ‘Types of outcomes’

  • Main outcomes, for inclusion in the ‘Summary of findings’ table, are those that are essential for decision-making, and should usually have an emphasis on patient-important outcomes.

  • Primary outcomes are the two or three outcomes from among the main outcomes that the review would be likely to be able to address if sufficient studies are identified, in order to reach a conclusion about the effects (beneficial and adverse) of the intervention(s).

  • Secondary outcomes include the remaining main outcomes (other than primary outcomes) plus additional outcomes useful for explaining effects.

  • Ensure that outcomes cover potential as well as actual adverse effects.

  • Consider outcomes relevant to all potential decision makers, including economic data.

  • Consider the type and timing of outcome measurements.