Key messages

- Passive dissemination of referral guidelines alone is unlikely to lead to improvements in referral practice.
- Guidelines for appropriate referral are more likely to be effective if:

− local secondary care providers are involved in dissemination activities;
− structured referral sheets are used.

- There is little evidence on the effects of organisational interventions but the use of \\\´in-house\\\´ second opinion and other intermediate primary care based alternatives to outpatient referral appear promising.
- Financial interventions can change referral rates but their effect on the appropriateness of referral is uncertain.
- All but one of the studies included in this review were from high-income countries.
Factors that should be considered in applying this evidence in low and middle-income countries include:

− the existence of a formal referral system and its ability to absorb additional referrals;
− the availability of resources to implement the intervention;
− the extent to which referrals are made by physicians or by other health workers.