The problem to determine the impact on digital communication systems of electromagnetic interference often requires complex calculations and analyses. Therefore, there is a need for approximate methods suitable for computer-based tools for intersystem interference analyses. A commonly used approximation is to treat the interference as if it is additive white Gaussian noise (AWGN) when estimating the resulting bit-error probability (BEP) for the digital communication system. However, the validity of this approximation varies for different types of interference. In this report, we show that it is possible to use higher-order statistics (HOS) as a quality measure of the AWGN-approximation. Furthermore, we also show that HOS can be used to quantify the impact on a digital communication receiver of some electromagnetic interference signals of interest. The results open up the possibility to use HOS as a quality measure of the resulting BEP when using approximate methods in computer-based tools.