Prospective meta-analysis is a method that has been utilized in recent years by trialists in cardiovascular disease (Simes 1995, WHO – ISI Blood Pressure Lowering Treatment Trialists' Collaboration 1998), childhood leukaemia (Shuster 1996, Valsecchi 1996) and childhood and adolescent obesity (Steinbeck 2006). In addition, some have identified areas, such as infectious diseases, where the opportunity to use PMA has largely been missed (Ioannidis 1999). The Cochrane Prospective Meta-analysis Methods Group web site includes a list of ongoing and completed PMA where further information can be found (Ghersi 2005).