The prioritisation tool that has been developed is highly innovative, since it is the only one of its kind that currently exists for automatically identifying and prioritising health technologies for which implementation of post-introduction observation would be especially relevant. It is a simple and easily usable tool, which is envisaged as being extremely useful for any institution/organisation proposing to implement a post-introduction observation system.

We feel that this tool has external validity, in view of the fact that members of all Spanish technology assessment agencies took part in its development and that the prioritisation criteria were selected and weighted by a group representative of all groups involved in the use of new technologies (medical managers/administrators, clinicians and patients).

The non collaboration of international experts in the elaboration of the criteria and weighting of the domains could de seen as a limitation to the extrapolation of criteria to other contexts. It could be argued that the criteria and weightings are not applicable in health systems with different characteristics and priorities, such as could be the case of United States. In our opinion, the proposed prioritisation criteria are equally valid in other international contexts, though we do not rule out the fact that slight differences may exist with regard to the relevance of such criteria. Similarly, there is also the possibility that additional criteria, not considered by the present working group, may be proposed. Although the prioritisation tool is proposed as a bench mark for prioritisation of new technologies, it is nonetheless envisaged that it may undergo slight modifications with the passage of time.