After finding the shortest conductive signal return-current path for each signal, the invention assesses whether each conductive return-current path is adequate. The method analyzes each shortest conductive signal return-current path and determines if a significant portion of the signal return current flows as displacement current rather than following the conductive current path. A significant displacement current flows when the length of the conductive return-current path that diverges from a signal net is more than a previously defined limit based on the signal transition time. Further, a significant displacement current flows when the overall length of the signal differs from the overall length of the conductive return-current path by more than a previously defined limit based on the signal transition time.