Differentially Private Synthetic Data: Applied Evaluations and Enhancements
This work addresses the problem of assessing and improving differentially private synthetic data for machine learning practitioners, though it is incremental as it builds on existing methods with applied evaluations.
The paper evaluates four differentially private generative adversarial networks for synthetic data generation on five tabular datasets and two industry scenarios, finding that some synthesizers perform better for different privacy budgets and proposing QUAIL, an ensemble approach that outperforms baseline models under the same privacy constraints.
Machine learning practitioners frequently seek to leverage the most informative available data, without violating the data owner's privacy, when building predictive models. Differentially private data synthesis protects personal details from exposure, and allows for the training of differentially private machine learning models on privately generated datasets. But how can we effectively assess the efficacy of differentially private synthetic data? In this paper, we survey four differentially private generative adversarial networks for data synthesis. We evaluate each of them at scale on five standard tabular datasets, and in two applied industry scenarios. We benchmark with novel metrics from recent literature and other standard machine learning tools. Our results suggest some synthesizers are more applicable for different privacy budgets, and we further demonstrate complicating domain-based tradeoffs in selecting an approach. We offer experimental learning on applied machine learning scenarios with private internal data to researchers and practioners alike. In addition, we propose QUAIL, an ensemble-based modeling approach to generating synthetic data. We examine QUAIL's tradeoffs, and note circumstances in which it outperforms baseline differentially private supervised learning models under the same budget constraint.