Synthetic data is one of the privacy enhancing technologies, which means that preserving the privacy of the original data used to create the synthetic data is of utmost importance and needs to be controlled. Synthetic data should be as close as possible to the original data, but not too close to allow any privacy attack. How close the synthetic data is to the original data can be tested and evaluated accordingly using privacy checks after each synthetization. The synthetic data generator should not overfit the original data and a privacy attacker should not be able to reveal any private and sensitive information about any person in the original data set.