A transmission line on a printed wiring board is tested and printed wiring board manufacturing variability is assessed. A response of the transmission line to a signal test pattern is measured. A network including a plurality of components connected by the transmission line is then simulated. The simulated network is based on the measured scattering parameters and virtual models representative of each of the components in the network. A system-level output response of the simulated network to a simulated input signal is analyzed, and the printed wiring board is characterized based on a comparison of the system-level output response to a printed wiring board performance metric threshold.