This glossary provides the terminology used in the Welfare Footprint Framework, together with their operational definitions. To differentiate these terms from their general usage, we recommend capitalizing them when referring to the definitions here.
Welfare: All affective states (negative and positive) experienced over a period of interest.
Welfare Footprint Framework: a scientific methodology for quantifying animal welfare and estimating animal welfare impacts by measuring the intensity and duration of animals’ experiences, both positive (pleasant) and negative (unpleasant). The framework has seven analytical modules that guide the analysis through a logical sequence: from a detailed description of the animal’s living circumstances (Module I: Zootechnical Description), to the identification of their biological consequences (Module II: Veterinary Inventory), to the quantification of each resulting affective experience in terms of intensity and duration (Module III: Affective Quantification), to the estimation of population-level burden (Module IV: Epidemiological Review), to the standardization of estimates per animal, unit of product or other parameter of interest (Module V: Econometric Calculation), to the transparent communication of results (Module VI: Welfare Footprint Expression and Notation). An optional module (Module Ψ: Interspecific Scaling) addresses comparisons across species. Central to this architecture is the causal cascade Circumstances → Biological Consequences → Affective Experiences, which distinguishes between the external circumstances animals face, the physiological and perceptual changes those circumstances produce, and the consciously felt states that the framework ultimately quantifies. The framework introduces innovative tools that enable transparent, evidence-based comparisons of animal welfare across interventions, systems, and food products (more information here).
Welfare Footprint: A quantitative measurement of the impact that actions or processes across different sectors have on animal welfare. These sectors include, but are not limited to, industrial, commercial, agricultural, research, and natural processes. Like in a life cycle analysis, a welfar footprint captures all welfare-relevant processes from birth to death for every animal involved—market animals, breeding stock, and ancillary species (e.g., fish used as feed). The metric quantifies three dimensions of animal experiences: (1) Intensity: How severe or pleasant each lived experience is (from Annoying to Excruciating; from Satisfaction to Bliss); (2) Duration: How long each experience lasts; (3) Prevalence: What proportion of animals experience it. These dimensions are combined to calculate total time spent in positive and negative states of varying intensities. Results can be standardized (i) per unit of product (e.g., 10 hours of severe Pain per kg meat); (ii) per person in a population; (iii) per unit of GDP, (iv) per dollar spent, among others, enabling direct comparison of welfare impacts between animal products, production methods, countries, companies, interventions, standards, or policy options.
Welfare Assessment (Guiding Principle): The guiding principle underlying the welfare assessments is a primary focus on the measurement of affective experiences. Aspects such as health, function and natural living are only important in this framework to the extent that they influence the subjective affective experiences of individuals. For example, subclinical health conditions, growth impairment or physical disabilities not associated with any type of unpleasantness (physical or psychological) in the short- or long-run are not considered relevant. Nor is the loss or deprivation of resources, or natural behaviors, that are not missed or valued by the animal (Dawkins, 2023). Affective experiences are taken as what matters to welfare.
Welfare indicators: discernable traits and signals that, based on evidence, are deemed to be correlated to a greater or lesser extent with an individual’s affective state. Indicators are often specific to a species or group of animals. They can include neurological, physiological, behavioral, environmental, pharmacological, immune and anatomical factors. Welfare indicators are typically characterized as resource-based, such as environmental factors like food and water availability, temperature, and space available, and animal-based, which include, among others, spontaneously occurring behaviors specific to Pain, changes in activity, social interaction patterns, attention and cognitive performance, vocalizations, facial expressions, neuroendocrine hormones, and autonomic responses (see more here).
Welfare metrics: quantitative constructs used to evaluate and compare animal welfare across different situations or over time. They are informed by welfare indicators and are often combined to create composite scores or indices that provide a more comprehensive assessment of animal welfare. Unlike welfare indicators, welfare metrics should be as universal and comparable as possible. Welfare metrics can be used to assess animal welfare in the field, inform decisions, or track progress. Examples of welfare metrics include the Cumulative Pain and Cumulative Pleasure (developed by the Welfare Footprint Framework), the Welfare Risk Scores developed by the European Food Safety Authority (EFSA) and in semantic models such as COWEL and SOWEL. Metrics used in assessments of animal welfare at the farm level include the scoring system of the Welfare Quality Protocol, AWIN Protocol and Animal Needs Index (see more here).
Figure 1. Animal welfare assessment process, from initial hazardous Circumstances through to the observable coping responses of organisms (e.g., behavioral and physiological indicators of pain). It categorizes indicators and links them to specific stages of the process leading to affective experiences. ‘Resource-based’ (upstream) indicators, represented by a tree symbol, correspond to four of the Five Domains. Numerous additional indicators are associated with different stages of the response process (with the mental state domain linked to the ‘Affective State (Pain)’ box). These indicators are essential for informing metrics and frameworks used in animal welfare assessments.
Species: The sentient species under examination or care.
System and Production System: The conditions in which the population of interest lives, encompassing everything from farming systems (e.g., intensive, semi-intensive, extensive), environments like zoos and sanctuaries, laboratory settings, natural habitats (wild animals) to socio-economic environments (in the case of humans).
Life-Fate: The roles or destinies of individuals within a species, characterized by the commonalities in critical life events and hazards they face (Alonso and Schuck-Paim 2017). For example, in a pig production system, different life-fates could include: (1) breeding females (sows): female pigs kept for reproductive purposes, (2) Market pigs: raised primarily for meat, (3) male breeders: male pigs kept for breeding purposes.
Life-Phases: The major life stages of a Life-Fate of interest, each presenting unique challenges and welfare implications. For example, in the case female breeding pigs, the following phases are present: (1) Suckling, (2) Postweaning, (3) Growth, (4) Pre-puberty, (5) Breeding Cycle: repetitive cycle involving conception, gestation, and farrowing, (6) Transportation, (7) Slaughter.
Circumstance: refers to the internal and external conditions—physical, social, environmental, genetic, and procedural—that shape the lives of animals during each Life-Phase. These include housing dimensions, resource availability, social configurations, management practices, and inherited traits such as breed or genotype. Crucially, Circumstances do not directly cause affective experiences, but do so through the Biological Consequences they generate. Examples of Circumstances include housing design, group size, lighting schedules, enrichment access, feeding regimes, handling methods, or genetic predispositions. These are described for each Life-Phase of every Life-Fate, as their combination sets the stage for how an animal’s biology responds to its environment. Where a Circumstance can vary meaningfully in magnitude (e.g., ammonia concentration, stocking density, infestation load), it may be disaggregated into severity categories when those differences are likely to produce distinct Affective Experiences.
Species-Specific Needs: The behavioral, spatial, physiological, and psychological requirements of a species that, when unmet, increase the likelihood of negative Affective States, and when met, promote positive ones.
Productivity metrics: The baseline output measures associated with the system under analysis (e.g., expected kilograms of meat, liters of milk, or number of eggs per animal). These figures are used in the Econometric Calculation (Module V) to standardize cumulative affective burdens and express the final Welfare Footprint per unit of output.
Processogram: A process diagram that conveys a time-ordered description of typical Life-Phases within a system or life stage of interest. Spatial components are represented as proportionally as possible to real-life conditions and are arranged along a horizontal axis representing the passage of time. Processograms are used to map Biological Consequences arising within each phase and to display the proportion of animals affected at the onset of each phase.
Biological Consequences: are the physiological, anatomical, neurological, or cognitive changes that result from an organism’s exposure to internal or external Circumstances, or from its own Affective Experiences. These consequences include not only physical manifestations (e.g., wounds, inflammation, metabolic imbalances), but also sensorial and perceptual states (e.g., detecting a threat, perceiving novelty, or recognizing a conspecific) that act as the proximate precursors of affective responses. Conversely, Affective Experiences—particularly when intense or prolonged—can generate or modulate Biological Consequences. For instance, chronic fear or stress may alter hormonal profiles. Biological Consequences are often multifactorial, resulting from multiple Circumstances. They can also cascade: an initial consequence (e.g., a fracture) may lead to secondary consequences (e.g., undernutrition due to limited food access). Not all Biological Consequences lead to an Affective Experience; subclinical conditions or immune suppression, for instance, may not give rise to downstream consequences that are consciously felt.
NEGATIVE
Negative Physical Consequences: Detrimental changes to the animal’s body or physiological state that arise from adverse circumstances or internal imbalances, leading to negative affective states.
Negative Perceptual Consequences: Blocking of psychological motivations (e.g., an animal is strongly driven to perform a behavior but is prevented from doing so), or changes in the animal’s perceptual state that elicit negative affect (e.g., perception of threat, social instability) without necessarily involving physical harm.
POSITIVE
Positive Physical Consequences: Fullfilment of motivations for physical needs, or changes in the animal’s physical state, that result in positive affective states (e.g., eating, drinking, copulation).
Positive Perceptual Consequences: Fullfiment of motivations for psychological needs (e.g., expression of behaviors), or changes in the animal’s perceptual state without necessarily arising from a pre-existing drive (e.g., spontaneous play, novel sensory stimuli) that elicit pleasure.
Note: When defining a perceptual Biological Consequence, terminology should remain strictly sensory or cognitive (e.g., ‘perception of social isolation’, ‘perception of maternal absence’, ‘perception of threat’). Emotionally loaded terms (e.g., ‘loneliness’, ‘sadness’, ‘fear’) are reserved exclusively for the resulting Affective Experience, which represents the actual consciously felt state.)
Pathway: Pathways are particular progressions through which a Biological Consequences unfolds in different groups of animals, leading to different types of Affective Experience. Common pathways include: Acute vs. Chronic, Fatal vs. Non-fatal.
Severity: Scale of the Biological Consequences, defined based on clinical or observable criteria (e.g., wound depth, disease stage, gait score). For example, a superficial scratch is less severe than a deep, infected wound. Standardized severity classifications (e.g., cancer staging, gait scores, body condition scores) are recommended where available, as they facilitate consistency across assessments and improve comparability.
Degree of Deprivation: The extent to which a behavioral or physiological motivation is thwarted. For example, a hen with no access to a nest may experience intense frustration, while one with a less preferred nest may experience a lower level of frustration. These are different affective experiences and must be disaggregated accordingly when possible.
Degree of Fulfillment: The extent a behavioral or physiological motivation is satisfied. For instance, the intensity of pleasure a hen pecking inert litter may experience is likely different than one foraging in a rich, rewarding substrate.
Affective Experience: The complete, dynamic emotional event or episode resulting from specific Biological Consequences. Affective experiences can be positive or negative. In the Welfare Footprint Framework, they are the overarching phenomena being evaluated and are referred to, generally, as ‘Pain from …’ and ‘Pleasure from …’, respectively.
Affective State: The specific condition or level of intensity an animal occupies at a given point in time during an Affective Experience (e.g., Annoying, Hurtful, Joy, Euphoria).
Temporal Segmentation: decomposition of an Affective Experience into meaningful time segments, each characterized by a relatively stable intensity.
NEGATIVE
Pain (Operational Definition): Broadly defined as any felt negative affective state. This includes both [physical pain], namely states with a somatic origin (e.g. aches, hunger, injuries, thermal stress) that are often the consequence of [Negative Physical Consequences], and [psychological pain], states related to the primary emotional systems (e.g. fear, frustration, boredom) that are often the consequence of [Negative Perceptual Consequences].
Pain (Proposal for a New Definition): Pain is a conscious experience, evolved to elicit corrective behavior in response to actual or imminent damage to an organism’s survival and/or reproduction. Still, some manifestations, such as neuropathic pain, can be maladaptive. It is affectively and cognitively processed as an adverse and dynamic sensation that can vary in intensity, duration, texture, spatial specificity, and anatomical location. Pain is characterized as ‘physical’ when primarily triggered by pain receptors and as ‘psychological’ when triggered by memory and primary emotional systems. Depending on its intensity and duration, pain can override other adaptive instincts and motivational drives and lead to severe suffering.
Pain Intensity: Intensity, when referred to in relation to pain, denotes the subjective measure of unpleasantness or aversiveness experienced by an individual at a point in time. This measure is not directly tied to the physical stimuli’s magnitude but rather to the personal, subjective experience of the pain’s severity or distress. Intensity is inferred from multiple streams of evidence (behavioral, physiological, neurological, pharmacological, and evolutionary) evaluated for their consistency with the operational criteria defining each intensity category.
Definition of Pain Intensity Categories: click here.
Pain-Track: A notation method for describing negative affective experiences based on their temporal evolution. It considers both the intensity and duration of pain for each phase of a pain episode, allowing for the integration of available scientific evidence. The horizontal axis represents time segments with flexible units (from milliseconds to years); the vertical axis represents intensity. Pain-Tracks enable the integration of available evidence into explicit, revisable hypotheses about the temporal dynamics of negative Affective Experiences.
Cumulative Pain: The total estimated time an individual or population spends in negative affective states of varying intensities (Annoying, Hurtful, Disabling, Excruciating). Rather than aggregating these experiences into a single weighted score, Cumulative Pain is maintained as a disaggregated metric, calculated by summing the time spent strictly within each distinct intensity category. For each temporal segment, the duration (often standardized in hours, and may exclude non-conscious periods such as sleep) is multiplied by the probability assigned to each intensity level; these products are then summed across all segments. The metric can be computed at different analytical levels, ranging from a single negative Affective Experience to the entire lifespan of a population, or standardized per unit of product. To ensure transparency and interpretability, it should always be presented with an explicit scope qualifier (e.g., Cumulative Pain [Episode], Cumulative Pain [Lifespan], Cumulative Pain [per kg]).
POSITIVE
Pleasure (WFF Operational Definition): any felt positive affective state.
Pleasure (extended WFF Definition): Pleasure is a conscious experience, evolved to elicit or reinforce behaviors beneficial to an organism’s survival and/or reproduction. It is affectively and cognitively processed as a positive and dynamic sensation that can vary in intensity, duration, texture, spatial specificity, and anatomical location. Pleasure is characterized as ‘physical’ when primarily triggered by stimuli that are directly rewarding or enjoyable, and as ‘psychological’ when triggered by cognitive processes, memories, and emotional states. Depending on its intensity and duration, pleasure can override other adaptive instincts and motivational drives, leading to states of dependency and self-damage.
Pleasure Intensity: Intensity, when referred to in relation to pleasure, denotes the subjective measure of pleasantness experienced by an individual. This measure is not directly tied to the stimuli’s magnitude but rather to the personal, subjective experience.
Definition of Pleasure Intensity Categories: click here
Pleasure-Track: a notation method for describing the positive affective experiences based on their temporal evolution. As with Pain-Tracks, each Affective Experience is decomposed into segments, with duration expressed as a range and intensity as a probability distribution across the defined intensity categories, reflecting both uncertainty and natural biological variation. It considers both the intensity and duration of pleasure for each phase of a pleasure episode, allowing for the integration of available scientific evidence.
Cumulative Pleasure: The total estimated time an individual or population spends in positive affective states of varying intensities (Satisfaction, Joy, Euphoria, Bliss). Rather than aggregating these experiences into a single weighted score, Cumulative Pleasure is maintained as a disaggregated metric, calculated by summing the time spent strictly within each distinct intensity category. For each temporal segment, the duration is multiplied by the probability assigned to each intensity level; these products are then summed across all segments. The metric is modular and can be computed at different analytical levels, ranging from a single positive Affective Experience to the entire lifespan of a population, or standardized per unit of product. To ensure transparency and interpretability, it should always be presented with an explicit scope qualifier (e.g., Cumulative Pleasure [Episode], Cumulative Pleasure [Lifespan], Cumulative Pleasure [per liter]).
Cumulative Affect: The umbrella term encompassing both Cumulative Pain and Cumulative Pleasure. It refers to the total estimated time an individual or population spends in Affective States of any valence and intensity over a period of interest. All Cumulative Affect estimates must specify a Scope Qualifier and must explicitly declare whether results are Baseline or Attention-Adjusted (see Module VI).
Target Population: A specific group of animals defined by shared characteristics, environments, and living conditions that form the boundary of the risk assessment. (EFSA, 2012).
Prevalence: proportion of the Target Population affected by a given Biological Consequence during the analyzed timeframe (e.g., the percentage of a flock with footpad dermatitis). When direct epidemiological data from commercial populations are available, they should be used. When they are not — which is the normal situation for most welfare conditions in most farmed species — prevalence may be constructed through reasoning: drawing on biological plausibility, knowledge of the mechanisms giving rise to the condition, analogies with related conditions, operational parameters from certification schemes or industry guidelines, and expert judgment. Estimates constructed through reasoning are not arbitrary; they are forms of knowledge that constrain what counts as a plausible scenario. They must, however, be clearly distinguished from empirically measured values, with the basis for each range explicitly stated. Prevalence estimates should be representative of the geographies, Production Systems, Life-Fates, and Life-Phases analyzed, and should be expressed as ranges to reflect both natural variation across subpopulations and epistemic uncertainty from data limitations, which are distinct sources of uncertainty and should be separated where the evidence allows. Point estimates should be avoided, as they mask true heterogeneity.
Occurrence: The number of times an affected animal typically contracts a given Biological Consequence during the analyzed timeframe. Occurrence is distinct from Prevalence: Prevalence describes how many animals are affected, while Occurrence describes how many times each affected animal experiences the condition.
Plausible Scenarios: set of conditions used to bound the space of welfare impacts that are plausible given current knowledge of a system. Because the Circumstances animals are exposed to vary across farms, regions, and over time, and are often not directly observed, welfare estimates must be tested across a range of conditions rather than anchored to a single assumed state. Plausible Scenarios are typically defined along a continuum anchored by two poles: a Best Practice Scenario, representing conditions that approach the standards of well-managed operations (e.g., compliance with certification requirements, optimal densities, handlers, equipment), and a Failure Scenario, representing conditions at the lower end of what is plausible (e.g., suboptimal handling, malfunction, high stocking densities, poor environmental control). Intermediate scenarios may be defined where the evidence supports finer distinctions. Plausible Scenarios are not worst-case or best-case bounds in an abstract sense; they are grounded in what is known about the range of real operating conditions within the analytical boundaries of the assessment. Their purpose is to ensure that conclusions are tested across the conditions animals may encounter, rather than derived from a single assumed typical state whose representativeness cannot be verified.
Sensitivity Analysis: procedure for testing whether welfare estimates hold across the range of Plausible Scenarios and uncertain parameter values defined in the assessment. Its purpose is not to validate input ranges against empirical reality, but to reveal which parameters matter most for a given conclusion. If conclusions hold across the full range of Plausible Scenarios the conclusion is robust to the uncertainty in question, and the poorly constrained parameter is of lower research priority. If it does not hold, sensitivity analysis identifies where better data would change the answer, directing empirical effort to where it is most consequential. Sensitivity analysis should test parameters both individually and in combination where non-independence among parameters is suspected. Results should allow examining how conclusions shift across the full space of plausible input combinations, rather than only whether a central estimate is stable to perturbations. Sensitivity analysis does substitute for missing data, but it can reveal whether missing data matters for the decision at hand.
Average Population Member. An analytical construct used to estimate the per-capita welfare burden of a Target Population. Because individuals within a population experience different hazards (e.g., a large fraction of broilers may experience lameness, but only a few experience fatal ascites), the WFF distributes the total population burden equally to determine the expected time in each affective intensity for a representative individual. This is calculated by multiplying the Cumulative Affect of an episode by the frequency of the Affective Experience and the prevalence of the underlying Biological Consequence. The final results must be expressed with an explicit Scope Qualifier (e.g., Cumulative Pain [Lifespan]).
Life-Fate Weighting: The process of aggregating Cumulative Pain and Cumulative Pleasure across multiple Life-Fates by their proportional representation in the population. Because different Life-Fates contribute unequally to a unit of product, their welfare burdens must be weighted accordingly before aggregation. For example, if there is one female breeder for every 150 market animals, the breeder’s welfare burden is distributed across her offspring in that ratio, and added to the market animal’s individual burden to produce a system-wide estimate per individual.
Welfare Footprint per Unit of Output: The standardized welfare burden expressed per unit of product (e.g., hours of Disabling Pain per kilogram of meat, per liter of milk, or per egg). This is calculated by dividing the system-wide Cumulative Pain or Pleasure estimate by the Productivity metrics established in Module I. Estimates should account for carcass yield, pre-slaughter mortality, and losses across the production chain, which reduce the average productivity per animal. Per unit estimates make visible the trade-offs in production systems where higher yields may reduce animal numbers but exacerbate individual welfare burdens.
Alternative Standardizations: In addition to standardization per unit of product, Welfare Footprint estimates can be expressed per person in a population (e.g., hours of Disabling Pain per capita per year), per unit of GDP, or per dollar spent. These alternative standardizations enable welfare impacts to be integrated into economic, environmental, and policy analyses, and facilitate comparisons across sectors, countries, and interventions beyond the level of individual products.
Traceability: The preservation of granular data from all prior modules within the final Welfare Footprint estimate, enabling welfare impacts to be traced back to their sources by Life-Fate, Life-Phase, or Biological Consequence. Traceability supports the identification of dominant contributors to Cumulative Pain and promoters of Cumulative Pleasure, and informs targeted and cost-effective interventions.
Analytical Boundaries: The scope of a Welfare Footprint assessment, encompassing the Life-Fates considered, Life-Phases , the Affective Experiences, species and Production System analyzed, and the geographical scope of the estimates. Analytical boundaries must be clearly defined to enable valid comparisons. Estimates from assessments with different analytical boundaries are not directly comparable without explicit reconciliation.
Scope Qualifier: An explicit label appended to any Cumulative Pain or Cumulative Pleasure estimate that specifies the analytical boundaries of the calculation in terms of the time period and level of analysis to which it applies. Without a Scope Qualifier, estimates from assessments with different boundaries are not directly comparable. A Scope Qualifier is mandatory in all published WFF estimates.
Cumulative Pain or Pleasure [Episode]: The total Cumulative Pain or Pleasure estimated for a single occurrence of an Affective Experience, as described in the corresponding Pain- or Pleasure-Track.
Cumulative Pain or Pleasure [Life-Phase]: The total Cumulative Pain or Pleasure accumulated by the average member of a Life-Fate across a defined Life-Phase, summing across all Affective Experiences occurring within that phase.
Cumulative Pain or Pleasure [Lifespan]: The total Cumulative Pain or Pleasure accumulated by the average member of a Life-Fate across their entire life, summing across all Life-Phases.
Cumulative Pain or Pleasure [per unit of product]: The total Cumulative Pain or Pleasure standardized per unit of output (e.g., per kilogram of meat, per liter of milk, per egg), as calculated in Module V.
Cumulative Affect [Baseline]: The default form of Cumulative Affect estimates, in which each Affective Experience is analyzed independently and results are summed across all experiences. The Baseline requires no data on comorbidity patterns or attentional competition, currently unavailable at scale. It is a transparent upper bound on cumulative welfare burden rather than a best estimate of what the animal is consciously experiencing at every moment.
Cumulative Affect [Attention-Adjusted]: An optional post-quantification refinement of the Baseline estimate that accounts for the competition between concurrent Affective States for the animal’s limited attentional resources. More intense Affective States capture a greater share of attention, potentially diminishing or blocking awareness of concurrent less intense states. Applying this adjustment requires data on comorbidity patterns, the frequency with which specific combinations of Affective Experiences co-occur, and on the attentional demand of each intensity level, neither of which are currently available at scale.
Hedonic Capacity: the maximum intensity of affective experience a species can plausibly reach. Hedonic capacity is plausibly variable across taxa, as with other biological features, but its nature and magnitude remain one of the major open questions in comparative biology and affective neuroscience.
Species-Internal Intensity Categories: The unqualified intensity terms used within the WFF (Annoying, Hurtful, Disabling, Excruciating; Satisfaction, Joy, Euphoria, Bliss) refer by default to categories used to classify time spent in different Affective States within a given species. They do not carry an implicit claim about how that species’ intensity range maps onto human experience. These terms are used in all intraspecific analyses.
Human-Anchored Reference Categories: Explicitly marked intensity categories — Annoying(h), Hurtful(h), Disabling(h), Excruciating(h) — used only when making interspecific comparisons. These categories serve as absolute calibration points against which other species’ intensity ranges can be positioned. Human-anchored categories are reference levels only; they are not asserted as universal ceilings, and values beyond Excruciating(h) cannot be ruled out in principle. This notation is introduced to preserve the integrity of intraspecific Welfare Footprint analyses while enabling explicit interspecific scaling when such comparisons are required.
Interspecific Scaling Correction: An optional post-quantification adjustment that maps a species’ internal intensity categories to human-anchored reference levels, accounting for potential differences in Hedonic Capacity and subjective time perception across taxa. All corrections must be reported and treated as provisional pending stronger evidence.
Natural Variation: Genuine biological differences in welfare outcomes across individuals, populations, farms, regions, and time. Natural variation exists in the world and will not be reduced by better measurement. It should be expressed as a range in all parameter estimates.
Epistemic Uncertainty: Uncertainty that reflects the limits of current evidence rather than genuine biological variation. Unlike natural variation, epistemic uncertainty can in principle be reduced by targeted data collection. Epistemic uncertainty and natural variation are distinct sources of imprecision and should be distinguished where possible in all parameter estimates.
Uncertainty Intervals (or Plausible Range): click here
