Insight into the effects and costs of information systems is becoming increasingly important. A key problem is to provide evidence which is transportable among sites. Transportability demands agreement on how to carry out assessment of information systems. In the VISTA study, three Dutch hospitals developed together an evaluation protocol for the assessment of the effects and costs of the nursing information system VISION. This protocol is based on a quasy-experimental study design allowing filtering for non-VISION influences. The protocol also included a uniform cost model. Based on a cost calculation for the three hospitals, the costs for hospital-wide implementation of VISION in a 445- and 800-bed hospital were extrapolated. VISTA is considered as a trial for application of one evaluation protocol at various sites. It is recommended to extend this national trial to a multi-national one, for instance by applying the cost model more broadly.
