The NAFEMS' mission statement is: 'To promote the safe and reliable use of finite element and related technology', so confidence in results is a key focus. The diverse nature of NAFEMS' technical working groups can provide insight into the specific issues in their technical areas that influence confidence in simulation results and in particular the challenges faced when validating simulations. To this end, representatives of each working group were asked to provide comments on the particular challenges of ensuring confidence in results for each of their focus areas.