BackgroundA serious game (SG) is a useful tool for nurse training. The objectives of this study were to assess validity evidence of a new SG designed to improve nurses’ ability to detect patient clinical deterioration.MethodsThe SG (LabForGames Warning) was developed through interaction between clinical and pedagogical experts and one developer. For the game study, consenting nurses were divided into three groups: nursing students (pre-graduate) (group S), recently graduated nurses (graduated < 2 years before the study) (group R) and expert nurses (graduated > 4 years before the study and working in an ICU) (group E). Each volunteer played three cases of the game (haemorrhage, brain trauma and obstructed intestinal tract). The validity evidence was assessed following Messick’s framework: content, response process (questionnaire, observational analysis), internal structure, relations to other variables (by scoring each case and measuring playing time) and consequences (a posteriori analysis).ResultsThe content validity was supported by the game design produced by clinical, pedagogical and interprofessional experts in accordance with the French nurse training curriculum, literature review and pilot testing. Seventy-one nurses participated in the study: S (n = 25), R (n = 25) and E (n = 21). The content validity in all three cases was highly valued by group E. The response process evidence was supported by good security control. There was no significant difference in the three groups’ high rating of the game’s realism, satisfaction and educational value. All participants stated that their knowledge of the different steps of the clinical reasoning process had improved. Regarding the internal structure, the factor analysis showed a common source of variance between the steps of the clinical reasoning process and communication or the situational awareness errors made predominantly by students. No statistical difference was observed between groups regarding scores and playing time. A posteriori analysis of the results of final examinations assessing study-related topics found no significant difference between group S participants and students who did not participate in the study.ConclusionWhile it appears that this SG cannot be used for summative assessment (score validity undemonstrated), it is positively valued as an educational tool.Trial registrationClinicalTrials.gov ID: NCT03092440