Every subsidy produces behaviour it did not intend. Understanding what a subsidy incentivises is as important as understanding what it rewards.
What Subsidies Do
A subsidy is any arrangement in which one actor bears a portion of the costs that another actor would otherwise bear, in order to encourage the subsidised actor to engage in more of the subsidised activity than they would without the subsidy. Subsidies are used by governments, institutions, and markets to correct for the systematic underproduction of activities whose social value exceeds their private return — activities that the unsubsidised market would produce less of than the social optimum requires.
The subsidy works as intended when the subsidised activity is genuinely underproduced by the unsubsidised market and when the subsidy increases the production of the activity without producing disproportionate unintended consequences. These conditions are met less often than subsidy designers expect, because subsidies change the incentive structures of all actors who interact with the subsidised activity — not only the actors the subsidy is designed to influence.
The Unintended Incentive Structure
Every subsidy creates an unintended incentive structure in addition to the intended one. The housing subsidy designed to increase affordable housing supply creates an incentive for developers to build to the subsidy's minimum standard rather than above it, and to classify as many units as possible as subsidy-eligible regardless of whether they serve the intended population. The agricultural subsidy designed to support small farmers creates an incentive for large agricultural operations to restructure in ways that qualify for the subsidy. The research subsidy designed to encourage basic science creates an incentive for researchers to describe applied work in the vocabulary of basic science.
These unintended incentive responses are not failures of ethics. They are rational responses to the incentive structure the subsidy creates. Actors respond to the incentives they face. When the subsidy creates incentives that diverge from the social objective the subsidy is designed to serve, actors will respond to the created incentives rather than the intended ones — producing the subsidy's fiscal cost without its intended social benefit.
Reading Subsidy Distortions
Reading the distortions a subsidy produces requires mapping the full incentive structure it creates, including the incentives for actors who were not the subsidy's intended beneficiaries but who are in a position to respond to the subsidy's existence. The analyst who maps only the intended incentive structure will predict that the subsidy produces its intended effect. The analyst who maps the full incentive structure will predict the distortions that the subsidy's unintended incentives produce — and will design the subsidy differently to reduce those distortions, or will recommend against the subsidy if the distortions exceed the intended benefit.
Every subsidy is simultaneously an intervention and an invitation — an invitation to every actor in the system to respond to the new incentive structure the intervention creates. The distortions that follow are not accidents. They are the rational responses the subsidy made possible.
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