A tool for evaluation of internal validity of in vitro studies called INVITES-IN is currently under development. The tool is designed specifically for cell culture studies. This protocol describes the testing of the performance of INVITES-IN. By performance, we mean the extent to which results of using INVITES-IN are the same for different users (consistency), the amount of time and cognitive effort it takes to apply INVITES-IN (assessor workload), the precision and potential for systematic error in results of applying INVITES-IN (accuracy), and how easy it is to use INVITES-IN (user experience). The participants in the user testing will be representative for the expected end-users of INVITES-IN which are persons preparing literature reviews including in vitro studies (e.g. in the context of chemical hazard and risk assessments or drug development). All end-users are expected to have experience with in vitro methods. Data collected from the performance testing will be used for further refinement and development of the release version of INVITES-IN.

Funding: The Swiss State Secretariat for Education, Research and Innovation (SERI) under contract no. 22.00230