The Interactive Tool for Closed-Loop Identification (ITCLI) is an interactive software tool for understanding SISO closed-loop identification using prediction-error techniques. The tool enables an interactive evaluation regarding how bias and variance effects play a role in identification under closed-loop circumstances. The role of external signal design, choice of model structure, controller tuning during identification testing, and signal injection points (at either the manipulated variable or the setpoint) all under the presence of autocorrelated disturbances are considered. The software is developed using Sysquake and is provided as a stand-alone executable version in mutilple operating environments.