The precision of interferometric measurements strongly depends on the system's calibration procedure, the stability of the illumination source and the quality of the scanner that moves the objective through focus. Typically, a calibration procedure is done prior to measurement and these measurement conditions are then assumed to be constant over time. Any variation in these conditons introduces errors into the measurement. Veeco's NT8000 optical profiler employs a calibration procedure that sharply decreases the system's sensitivity to changes in measurement conditions. It is a system that is independent of any geometrical standards and one that is capable of self-calibration during each measurement. This hands-off self-calibrating feature allows for high repeatability, reproducibility and accuracy of measurements and excellent sytem to system correlation. These measurement features make such a system ideally suited for production lines, laboratories and standardization institutes.