Recently a complete model of JET polarimeter calibration has been developed. In this paper, this model has been checked using residual analysis. The differences between the estimates of the calibration code and the experimental measurements, for both manual and automatic calibrations, have been calculated and tested statistically. The correlation analysis of the residuals, performed with methods valid also for nonlinear systems such as JET polarimeter, confirms the quality of the model developed to interpret the calibration of the diagnostic.