Provided are process control methods and process control systems. The method includes performing a deposition process on a lot defined by a group of a plurality of wafers, performing a measurement process on the lot to obtain a measured value with respect to at least one wafer among the plurality of wafers, producing a target value of a factor of a process condition in the deposition process by using a difference between the measured value and a reference value, and providing an input value of the factor with respect to a subsequent lot based on the target value. The operation of providing the input value of the factor includes obtaining a previous target value of the factor previously produced with respect to at least one previous lot, and providing a weighted average of the previous target value and the target value as the input value.