Policymakers often use benefit-cost analysis (BCA) to bring objectivity to policy analysis by converting the pros and cons of different options into monetary terms. This approach helps allocate limited resources efficiently and maximize their societal benefits. Despite the recognized effect human activities have on animal lives, their welfare is typically excluded from these analyses due to the absence of quantitative methods that can monetize both human and animal welfare on a common scale. As much as advocates may wish for a more compassionate worldview, without quantifying animal welfare, many policymakers can’t fully understand how their decisions impact the quality of animal life.

The authors explain that there is no universally accepted method to measure the intrinsic value of animal welfare, which is considered a “non-market good” — a resource that provides societal value but isn’t bought or sold in traditional markets. A common practice for monetizing non-market goods is human willingness-to-pay (WTP), an economic tool that assesses how much people are willing to spend to secure or improve goods like recreation and clean air. WTP is frequently applied to animal welfare, translating public preferences into monetary terms. However, because WTP reflects human biases, knowledge, and income levels, the authors argue that it inherently has nothing to do with an animal’s actual well-being.

The authors propose adapting the Quality-Adjusted Life Years (QALYs) metric, which is commonly used in human health economics, into the novel Animal Quality-Adjusted Life Years (AQALYs). QALYs measure both the quality and quantity of human life, where one QALY represents one year of perfect health. Similarly, AQALYs quantify animal welfare by assessing how well an animal’s needs are met throughout its lifetime. The proposed method incorporates existing animal welfare frameworks like the Five Freedoms, which evaluates an animal’s freedom from hunger, discomfort, pain, and fear, along with the ability to express natural behaviors. Combined with lifespan, this produces an AQALY score, where higher scores indicate better welfare. Policymakers can then convert these scores into monetary values, allowing them to weigh animal welfare in BCA for decisions on agricultural and environmental practices, laws, and protections.

To demonstrate the AQALY concept, the authors compare the welfare of egg-laying hens in conventional battery cages versus larger cages with enrichment. They estimate that hens in conventional cages score 0.2 AQALYs per year due to poor living conditions, whereas hens in enriched cages score 0.6 AQALYs per year. Over two years, this results in 0.4 AQALYs for battery hens and 1.2 AQALYs for those in enriched cages, representing a 0.8 AQALY improvement. This difference can then be monetized and included in policy decisions to promote better animal welfare.

The AQALY framework, while promising, has notable limitations. One fundamental challenge is that not all species experience welfare in the same way, complicating efforts to develop a standardized measure comparable to human welfare. To address this, the authors introduce “welfare potential,” which adjusts AQALY scores based on the cognitive and emotional capacities of different species, allowing for more refined comparisons between animals and humans. Two methods for estimating welfare potential are suggested:

• Time Trade-Off Method: People are surveyed to determine how many years of human life they would trade to live as an animal of a specific species.

• Biological Proxies: This method estimates welfare potential by evaluating biological and behavioral traits, such as brain size and cognitive abilities, offering a comparison between animal and human well-being. 

Though a step in the right direction, the authors acknowledge that these methods also have limitations. The time-trade off method risks bias, as humans may not fully empathize or understand animal experiences. Using biological proxies assumes cognition directly correlates with welfare, which can oversimplify animal well-being. 

Additionally, AQALYs, which focus on the welfare of individual animals over their lifetimes, do not intrinsically account for changes in animal populations resulting from policy shifts, such as fluctuations in population sizes due to changes in meat consumption or habitat policies. This oversight can lead to incomplete assessments of policy impacts. Political feasibility is also a concern, as some people may resist reform if prioritizing animal welfare conflicts with human interests. 

The authors conclude that, because animals cannot directly advocate for their own welfare and market-based solutions may prove inadequate, ensuring that animal welfare is fully considered in policy decisions will require strong altruistic motivations and comprehensive reforms. Despite the challenges, integrating animal welfare into BCA may be one of the most effective ways to promote compassionate and equitable policies that account for the well-being of all affected species in the long term.