We propose that the logic of a genie – an agent that exploits an ambiguous request to intentionally misunderstand a stated goal – underlies a common and consequential phenomenon, well within what is currently called proxy failures. We argue that such intentional misunderstandings are not covered by the current proposed framework for proxy failures, and suggest to expand it.

One example of proxy failure is current antisexist and antiracist policies. One of the most popular proxy in them is the number of representatives of marginalized groups – women and nonwhite people – in power structures. Here I show that such measures do not lead to combating sexism and racism, which flourish despite their application.

The notion of proxy failure provides considerable insight into educational processes, and in childhood education has the potential to elucidate known problems stemming from the early implementation of overly regulated educational regimes. This commentary expands on play and how its relation to learning provides a useful perspective on how activities based on nongoal-oriented interactions can lead to desired outcomes.

Reductionist methodologies reduce phenomena to some of their lower-level components. Researchers gradually shift their focus away from observing the actual object of study toward investigating and optimizing such lower-level proxies. Following reductionism, these proxies progressively diverge further from the original object of study. We vividly illustrate this in the evolution of target-based drug discovery from rational and phenotypic drug discovery.

Utilitarian characterizations of economic decision making fail to capture the complex, conditional, and heterogeneous motivations underlying human behavior as shaped by the predictive, multicriterial drivers of biological regulation. Unless economic models start to acknowledge that humans have bodies and a biology with its own adaptive logic and tradeoffs, economic policies will be systematically exposed to, and systematic generators of, proxy failures.

Social media takes advantage of people's predisposition to attend to threatening stimuli by promoting content in algorithms that capture attention. However, this content is often not what people expressly state they would like to see. We propose that social media companies should weigh users’ expressed preferences more heavily in algorithms. We propose modest changes to user interfaces that could reduce the abundance of threatening content in the online environment.

The analysis of John et al. is lacking a fully general account of proxy failure. It is here proposed that proxy failure can be understood as a feature of all adaptive control systems. Whether proxies “fail” or “succeed” depends on the more encompassing view one can adopt for observing such systems.

Two of John et al.'s examples of proxy failures in ecological situations are not failures: Runaway sexual selection and marsupial neonate competition. Instead, more appropriate ecological examples may be paternal genetic kin recognition and warning coloration. These differ in proxy effectiveness and failure in ways that illustrate the importance of “costs” in the evolution of ecological proxy traits.

I consider the dynamics of regulator–agent interactions in situations in which there are significant mismatches in their abilities to discern and register information and calculate and act upon successful inferences.

We argue that a diverse and dynamic pool of agents mitigates proxy failure. Proxy modularity plays a key role in the ongoing production of diversity. We review examples from a range of scales.

Following John et al., we provide examples of failing proxies that might help to contextualize the role of proxy failures in applied research. We focus on examples from the sociology of science and illustrate how the notion of proxy failure can sharpen applied analysis, if used in a way that does not obscure other dysfunctional effects of proxies.

We argue that proxy failure contributes to poor measurement practices in psychological science and that a tradeoff exists between the legibility and fidelity of proxies whereby increasing legibility can result in decreased fidelity.

Identifying the conditions of proxy treadmilling is crucial for determining whether reliable signals can persist over time. I present a framework that maps evolutionary models of reliable signals according to their assumptions regarding the effects of Goodhart's law. This framework can explain the contrasting outcomes of different modelling approaches, and identify in which models proxy treadmilling is expected to occur.

A societal shift has occurred toward making impactful decisions on the basis of objective metrics rather than subjective impressions. This shift is commonly justified by claims that we should not trust subjective intuitions. These are often unjust and thereby corrupt. However, the proxies used to make objective decisions are subject to a different form of corruption, characterized as proxy failure.

Proxies should not be classified as failures or successes because, in most cases, they are impossible translations of abstract, polysemous goals to supposedly univocal concrete measures. The “success” or “failure” of a proxy does not depend on its actual accuracy as a valid indicator of goal attainment, but on a social system's willingness to maintain an illusion of its accomplishment.

Decision-making heuristics rely on proxies so the elements of heuristics appear to map well to the elements of proxies identified by John et al. However, unlike proxy failure, heuristics do not fail because of feedback. This may be because for successful heuristics the goals of regulators and agents are aligned, but this is not the case for proxy failure.

In their target article, John et al. make a convincing case that there is a unified phenomenon behind the common finding that measures become worse targets over time. Here, we will apply their framework to the domain of animal welfare science and present a pragmatic solution to reduce its impact that might also be applicable in other domains.

The analysis of proxy failure given by John et al. provides a good starting point for interdisciplinary discussions. Here, the discussion of teleonomy is extended and updated to include more recent discourse on the topic.

Natural selection is slow, so behavioral goals must be based on patterns of reward. Addictions are rewarded in the same way as adaptive choice, so they can be distinguished only by their time course. In addition, the reward process is more plastic than is generally recognized, so abstract goals are shaped by the “legibility” of their proxies.

When a measure becomes a target, it ceases to be a good measure. For example, when standardized test scores in education become targets, teachers may start “teaching to the test,” leading to breakdown of the relationship between the measure – test performance – and the underlying goal – quality education. Similar phenomena have been named and described across a broad range of contexts, such as economics, academia, machine learning, and ecology. Yet it remains unclear whether these phenomena bear only superficial similarities, or if they derive from some fundamental unifying mechanism. Here, we propose such a unifying mechanism, which we label proxy failure. We first review illustrative examples and their labels, such as the “cobra effect,” “Goodhart's law,” and “Campbell's law.” Second, we identify central prerequisites and constraints of proxy failure, noting that it is often only a partial failure or divergence. We argue that whenever incentivization or selection is based on an imperfect proxy measure of the underlying goal, a pressure arises that tends to make the proxy a worse approximation of the goal. Third, we develop this perspective for three concrete contexts, namely neuroscience, economics, and ecology, highlighting similarities and differences. Fourth, we outline consequences of proxy failure, suggesting it is key to understanding the structure and evolution of goal-oriented systems. Our account draws on a broad range of disciplines, but we can only scratch the surface within each. We thus hope the present account elicits a collaborative enterprise, entailing both critical discussion as well as extensions in contexts we have missed.