Sequential Strategic Screening

TL;DR

This paper explores strategic behavior in sequential screening processes, revealing how individuals can exploit the order of classifiers to manipulate outcomes and proposing methods to design robust screening pipelines.

Contribution

It introduces the concept of sequential screening, analyzes individuals' strategic manipulation, and develops a learner approach to create manipulation-resistant screening processes.

Findings

Individuals can exploit sequential order to manipulate outcomes.

Limited manipulation can succeed even when far from positive regions.

A construction for robust sequential screening design is proposed.

Abstract

We initiate the study of strategic behavior in screening processes with multiple classifiers. We focus on two contrasting settings: a conjunctive setting in which an individual must satisfy all classifiers simultaneously, and a sequential setting in which an individual to succeed must satisfy classifiers one at a time. In other words, we introduce the combination of strategic classification with screening processes. We show that sequential screening pipelines exhibit new and surprising behavior where individuals can exploit the sequential ordering of the tests to zig-zag between classifiers without having to simultaneously satisfy all of them. We demonstrate an individual can obtain a positive outcome using a limited manipulation budget even when far from the intersection of the positive regions of every classifier. Finally, we consider a learner whose goal is to design a sequential screening process that is robust to such manipulations, and provide a construction for the learner that optimizes a natural objective.