Standardized Measurement Error as a Universal Measure of Data Quality for Event-Related Potentials: An Overview

Although it is widely understood that event-related potentials (ERPs) can be very noisy, the field has no widely accepted metric of ERP data quality. Here we propose a universal measure of data quality for ERP research, the standardized measurement error (SME). The SME is a simple extension of the widely used standard error of measurement, but it quantifies the error of single-participant measurements rather than group values. In addition, the SME quantifies data quality with respect to the specific amplitude or latency value being measured in a given study (e.g., the peak latency of the P3 wave). The SME is trivial to compute during the averaging process for linear measures such as mean amplitude, and it can be extended to virtually any amplitude or latency measure via a straightforward bootstrapping approach.