Syntho’s QA report contains three industry-standard metrics for evaluating data privacy. The idea behind each of these metrics is as follows: Synthetic data (S) shall be “as close as possible”, but “not too close” to the target data (T). Randomly selected holdout data (H) determines the benchmark for “too close”. A perfect solution generates new synthetic data that behaves exactly like the original data, but hasn’t been seen before (= H).