Strategic Classification is Causal Modeling in Disguise
This work addresses a foundational challenge in consequential decision-making for AI systems, revealing that prior strategic classification efforts are essentially causal modeling, which is incremental in clarifying theoretical obstacles.
The paper tackles the problem of distinguishing between gaming and genuine improvement in strategic classification by developing a causal framework, proving that designing classifiers to incentivize improvement inherently requires solving non-trivial causal inference problems.
Consequential decision-making incentivizes individuals to strategically adapt their behavior to the specifics of the decision rule. While a long line of work has viewed strategic adaptation as gaming and attempted to mitigate its effects, recent work has instead sought to design classifiers that incentivize individuals to improve a desired quality. Key to both accounts is a cost function that dictates which adaptations are rational to undertake. In this work, we develop a causal framework for strategic adaptation. Our causal perspective clearly distinguishes between gaming and improvement and reveals an important obstacle to incentive design. We prove any procedure for designing classifiers that incentivize improvement must inevitably solve a non-trivial causal inference problem. Moreover, we show a similar result holds for designing cost functions that satisfy the requirements of previous work. With the benefit of hindsight, our results show much of the prior work on strategic classification is causal modeling in disguise.