This paper is concerned with the estimation of a suitable explicit expression for the feedback controller-invariant term of the closed-loop MIMO process from routine operating data. The feedback controller-invariant or the minimum-variance term is subsequently used as benchmark standard for the evaluation of control performance of MIMO processes. This new approach, towards control-loop performance analysis of closed-loop MIMO processes, is based on filtering and correlation (FCOR) analysis of the process output and filtered data. The FCOR algorithm is intuitively simple and computationally efficient. However, it does require a priori knowledge or estimation of the time-delay or interactor matrix of the MIMO process. The proposed algorithm is evaluated by application to simulated and industrial processes.