The Continuous Performance Critical Stability Task (cpCST) is a continuous performance task that provides high temporal resolution, time-varying estimates of a user’s ability to maintain task focus. The task is an extension of the Critical Stability Task (Jex, et al, 1966), where participants are presented with a stimulus disk at the center of the screen, which drifts to the left or right. They are asked to compensate for the stimulus movements and keep the stimulus at the center of the screen. In the cpCST, users perform this task in two distinct phases: a calibration phase and a continuous performance phase. During the calibration phase, the stimulus will become increasingly unstable until the user can no longer control the position of the stimulus. This is repeated for several trials to estimate the maximal amount of instability the user can manage (denoted as lambda_max). Following calibration, users complete the continuous performance phase. Here, the task proceeds much as in the calibration phase, but the system instability is fixed at just 30% of the user’s lamba_max value. Simulus position and user responses are continuously sampled 60 times per second over a 10-minute trial, allowing high resolution momentary estimates of task error and latency to respond to stimulus movements.