Discussion: There is a growing recognition of the need both for economic evaluations to use the results of systematic reviews of effectiveness, and for trials to include measures required for economic evaluation. It is therefore important to think about how reviews of such trials may inform questions of cost-effectiveness. The effects of surfactant on the costs, and therefore the cost-effectiveness, of neonatal care are beginning to be reported in different studies. We have reviewed the trials to establish which data could be used in economic evaluation, in what ways the trials could contribute to a generalisable economic evaluation, and what we could recommend that future trialists and reviewers could do to make their research more useful for economic evaluation. Six out of 17 trials examined included some measurement of the care process, such as length of time on the ventilator. Three of these trials were designed to inform economic analyses, reported separately. The results of these economic analyses were based on estimates of effectiveness from single trials. We show how using pooled data about effectiveness would change the estimates of cost-effectiveness from these studies, and discuss whether pooling cost data from different studies could improve generalizability of an economic evaluation of surfactant.