Legal

The metric

The WFF keeps three things apart: the circumstances an animal was in, the biological consequences of those circumstances (such as injury, disease or deprivation), and the experiences that follow from them. This shows which conclusions rest on facts in evidence and which rest on scientific inference.

A Pain-Track divides an experience into time segments and gives, for each segment, the probability of each of four intensities: Annoying, Hurtful, Disabling and Excruciating. Each assessment is documented with the behavioural, physiological, neurological and pharmacological evidence that supports or contradicts it. Cumulative Pain is the time spent at each intensity. Each intensity is reported separately, with a range, so no weighting is hidden in a single score. Where the evidence cannot separate two intensities, the assessment says so in probabilities. An opposing expert or the court can then see where an estimate is strong and where it rests on limited data, and test how the result changes under other assumptions.

Intensity and duration are estimated by synthesizing behavioural, neurophysiological, pharmacological and evolutionary evidence against defined criteria, and are expressed as probabilities across four intensity categories rather than a single value. Prevalence comes from epidemiological evidence; where data are thin, it is given as an uncertainty interval. Each parameter is treated as a hypothesis with a stated uncertainty, and is updated as evidence accumulates. The main limitations, mostly sparse data on timing and prevalence, are set out in the FAQ. The framework does not prescribe whether to improve current systems or move away from them. It makes the welfare consequences of each option comparable. The method is the same for every estimate. What varies is the scope (species, system, life stages and region), and each estimate states its boundaries.

Start here: What is a welfare footprint? · The framework · Pain intensities · Uncertainty intervals

Where the framework can help

• Cruelty and neglect cases. Many legal systems require proof that an animal experienced severe or prolonged pain and distress. Assessments have often relied on expert opinion alone, which can vary between evaluators. The WFF documents how long each negative experience lasted, how intense it was in each phase, the evidence for each assessment and the cumulative impact over time. Whether the facts are proven, whether the evidence is admissible and whether the legal threshold is met remain for the court. Professionals from Costa Rica's National Animal Health Service (SENASA) and Judicial Investigation Agency (OIJ) explored this use in a two-day workshop (Using the Welfare Footprint Framework to document animal welfare in legal settings).
• Legal welfare standards. Some laws set tests in terms of unnecessary or avoidable pain and distress. Where a law does, the estimates can describe how intense and how long the pain is under a practice and under its alternatives, and what the alternatives cost. A WFF study of rainbow trout at slaughter, for instance, compared air asphyxia with electrical and percussive stunning (Schuck-Paim et al., 2025, Scientific Reports 15:19850, doi:10.1038/s41598-025-04272-1; see also news). Whether pain is avoidable in the legal sense is a question of law.
• Legislation and regulatory impact assessment. Options can be compared in one unit, time at each intensity of pain, and set against their cost. Standards can also be written in time-based terms (FAQ).
• Consumer protection and advertising. A welfare claim can be checked against what was actually estimated, whether you are substantiating it or challenging it. A specific statement with a range, scope and source can be tested in a way a general claim cannot. An estimate that covers only the harms analysed is a minimum, and a finding about a production system needs evidence that the claimant's own supply matches the scenario studied. In the EU, Directive (EU) 2024/825 (EmpCo) applies the rules on misleading practices to claims about a product's social characteristics. Its recitals say these can include animal welfare.
• Due diligence and disclosure. Sustainability reporting increasingly covers animal welfare. For example, the European Sustainability Reporting Standards list it as a business-conduct matter (ESRS G1). A common unit helps make disclosures specific and comparable.
• Trade and equivalence of standards. Where the question is whether rules in different jurisdictions achieve comparable welfare, estimates in a common unit let you compare what the rules achieve, not only what they say. This works where estimates exist for each system being compared.
• Legal scholarship and teaching. The framework can support research on how the law describes and weighs animal welfare, as well as courses and clinic projects.

Using the estimates responsibly

• Report the range and uncertainty, and keep "at least" where an estimate is a minimum.
• Keep the intensity categories separate. Don't merge them into a single score.
• Match the scope: species, system, region, comparator, time period and the harms analysed. A finding about a production system does not, by itself, establish facts about a particular company, product or case.
• Keep the scientific finding separate from your legal argument or conclusion.
• Cite the version and date of the estimate you use, and link the source.
• Cite the framework as: Alonso, W. J., & Schuck-Paim, C. (2025). Welfare Footprint Framework: Methodological Foundations and Quantitative Assessment Guidelines. Center for Welfare Metrics (São Paulo). https://doi.org/10.17605/osf.io/94bxs Download PDF
• Outputs of the AI-Assisted Tools are not WFI estimates. Present them as your own preliminary assessment and have an expert review them.
• Avoid wording that suggests WFI endorses a party, product or position. All estimates are free to use under CC BY 4.0.

Keep going

• Find what has been estimated: Publications · Estimates Dossier (still being built)
• Learn the method: Workshops · Office Hours · Teaching materials
• Tell us about a legal question where evidence on animal pain would help, or how you have used an estimate, using the form below.

Your question

Or email contact@welfarefootprint.org.