Publisher Summary This chapter discusses that a major challenge for electromyographers is deciphering motor unit potential (MUP) morphology and firing patterns that represent subtle departures from the limits of a normal population of MUPs. While most electromyographers are adept at using qualitative techniques to examine patients with very mild or questionable disease, and can make an accurate diagnosis, there is merit to using quantitative techniques. The chapter reviews and compares efforts to analyze the interference pattern fall into four broad categories: measurement of amplitude, analysis of frequency and power spectrum, spike counting, and most recently decomposition of the motor unit firing rates. Individual MUPs can be isolated from the decomposed firing rates and analyzed for duration, amplitude, morphology, rise time, firing pattern, and other attributes. Efforts to assess MUPs across the spectrum of muscle contractions focus on analyzing aggregate MUP activity rather than on individual MUPs. It is termed as interference pattern analysis (IPA). These techniques rely on computer-based algorithms to work in a semiautomated manner and are available on many commercial electromyography (EMG) systems.