IntroductionAlthough robotic-assisted surgery is increasingly performed, objective assessment of technical skills is lacking. The aim of this study is to provide validity evidence for objective assessment of technical skills for robotic-assisted surgery.MethodsAn international multicenter study was conducted with participants from the academic hospitals Heidelberg University Hospital (Germany, Heidelberg) and the Amsterdam University Medical Centers (The Netherlands, Amsterdam). Trainees with distinctly different levels of robotic surgery experience were divided into three groups (novice, intermediate, expert) and enrolled in a training curriculum. Each trainee performed six trials of a standardized suturing task using the da Vinci Surgical System. Using the ForceSense system, five force-based parameters were analyzed, for objective assessment of tissue handling skills. Mann–WhitneyUtest and linear regression were used to analyze performance differences and the Wilcoxon signed-rank test to analyze skills progression.ResultsA total of 360 trials, performed by 60 participants, were analyzed. Significant differences between the novices, intermediates and experts were observed regarding the total completion time (41 s vs 29 s vs 22 sp=0.003), mean non zero force (29 N vs 33 N vs 19 Np= 0.032), maximum impulse (40 Ns vs 31 Ns vs 20 Nsp= 0.001) and force volume (38 N3vs 32 N3vs 22 N3p= 0.018). Furthermore, the experts showed better results in mean non-zero force (22 N vs 13 Np= 0.015), maximum impulse (24 Ns vs 17 Nsp= 0.043) and force volume (25 N3vs 16 N3p= 0.025) compared to the intermediates (p≤ 0.05). Lastly, learning curve improvement was observed for the total task completion time, mean non-zero force, maximum impulse and force volume (p≤ 0.05).ConclusionConstruct validity for force-based assessment of tissue handling skills in robot-assisted surgery is established. It is advised to incorporate objective assessment and feedback in robot-assisted surgery training programs to determine technical proficiency and, potentially, to prevent tissue trauma.Supplementary InformationThe online version contains supplementary material available at 10.1007/s00464-023-09905-y.