Private False Discovery Rate Control

TL;DR

This paper introduces the first differentially private algorithms for controlling the false discovery rate in multiple hypothesis testing, adapting the BHq procedure and ensuring robust FDR control with minimal power loss.

Contribution

It develops differentially private FDR control algorithms based on a new proof of BHq's robustness under weak independence assumptions.

Findings

Achieves FDR control with minimal power loss under differential privacy.

Introduces a low-distortion 'one-shot' private primitive for top-k problems.

Provides a new privacy proof technique for top-k algorithms.

Abstract

We provide the first differentially private algorithms for controlling the false discovery rate (FDR) in multiple hypothesis testing, with essentially no loss in power under certain conditions. Our general approach is to adapt a well-known variant of the Benjamini-Hochberg procedure (BHq), making each step differentially private. This destroys the classical proof of FDR control. To prove FDR control of our method, (a) we develop a new proof of the original (non-private) BHq algorithm and its robust variants -- a proof requiring only the assumption that the true null test statistics are independent, allowing for arbitrary correlations between the true nulls and false nulls. This assumption is fairly weak compared to those previously shown in the vast literature on this topic, and explains in part the empirical robustness of BHq. Then (b) we relate the FDR control properties of the differentially private version to the control properties of the non-private version. \end{enumerate} We also present a low-distortion "one-shot" differentially private primitive for "top $k$" problems, e.g., "Which are the $k$ most popular hobbies?" (which we apply to: "Which hypotheses have the $k$ most significant $p$-values?"), and use it to get a faster privacy-preserving instantiation of our general approach at little cost in accuracy. The proof of privacy for the one-shot top~$k$ algorithm introduces a new technique of independent interest.