A phased array antenna (PAA) system can be calibrated by using several methods. In general, the aim of this calibration is to guarantee that the systematic errors are diminished. Still there can be residual errors due to the random errors in the system. These residual errors may decrease the correction accuracy of the calibration. This correction accuracy can be quantified as a quality factor. In this paper, quality of the Rotating Electric-Field Vector (REV) calibration method is examined with a statistical approach. Also, a statistical approach for PAA error analysis is developed for this purpose. This approach is used for the first time for a specific calibration method.