Variability

{
  "id": "MLC-T-ENV-029512",
  "term": "Variability",
  "field": "Environment",
  "definition": "1. Variability refers to observed differences attributable to true heterogeneity or diversity. Variability is the result of natural random processes and is usually not reducible by further measurement or study (although it can be better characterized).\n\n2. Variability refers to true heterogeneity or diversity. For example, among a population that drinks water from the same source and with the same contaminant concentration, the risks from consuming the water may vary. This may be due to differences in exposure (i.e., different people drinking different amounts of water and having different body weights, different exposure frequencies, and different exposure durations) as well as differences in response (e.g., genetic differences in resistance to a chemical dose). Those inherent differences are referred to as variability. Differences among individuals in a population are referred to as inter-individual variability, differences for one individual over time is referred to as intra-individual variability.\n\n3. This refers to the range of toxic response or exposure - for example, the dose that might cause a toxic response can vary from one person to the next depending on factors such as genetic differences, preexisting medical conditions, etc. Exposure may vary from one person to the next depending on factors such as where one works, time spent indoors or out, where one lives, how much people eat or drink, etc.\n\n4. Refers to the range of toxic response or exposure. For example, the dose that might cause a toxic response can vary from one person to the next depending on factors such as genetic differences, preexisting medical conditions, etc. Exposure may vary from one person to the next depending on factors such as where one works, time spent indoors or out, where one lives, how much people eat or drink, etc.\n\n5. Imprecision about a specific characteristic.\n\n6. Differences among entities or states of an entity attributable to heterogeneity. Variability is an inherent property of nature and may not be reduced by measurement.\n\n7. Variability arises from true heterogeneity across people, places or time and can affect the precision of exposure estimates and the degree to which they can be generalized. The types of variability include: spatial, temporal, and inter-individual.\n\n8. Observable diversity in biological sensitivity or response, and in exposure parameters (such as breathing rates, food consumption, etc.) These differences can be better understood, but generally not reduced by further research.\n\n9. Refers to the observed differences attributable to true heterogeneity or diversity in a population or exposure parameter. Examples include human physiological variation (e.g., natural variation in body weight, height, breathing rate, drinking water intake rate), weather variability, variation in soil types and differences in contaminant concentrations in the environment. Variability is usually not reducible by further measurement of study, but it can be better characterized.\n\n10. A description of differences among the individual members of a series or population.\n\n11. Refers to observed differences attributable to true heterogeneity or diversity. Variability is the result of natural random processes and is usually not reducible by further measurement or study (although it can be better characterized).\n\n12. True heterogeneity or diversity in characteristics among members of a population (i.e., inter-individual variability) or for one individual over time (intra-individual variability). For example, body weights of a study population at one point in time will exhibit variability, and body weight will change as an individual ages. Further study (e.g., increasing sample size, n) will not reduce variability, but it can provide greater confidence in quantitative characterizations of variability.\n\n13. Observed differences attributable to true heterogeneity or diversity. Variability is the result of natural random processes and is usually not reducible by further measurement or study (although it can be better characterized) (EPA 1997).\n\n14. Variability arises from true heterogeneity across people, places, or time and can affect the precision of exposure estimates and the degree to which they can be generalized. The types of variability include: spatial, temporal, and inter-individual. [EPA 1997a]\n\n15. Variability refers to true heterogeneity or diversity. For example, among a population that drinks water from the same source and with the same contaminant concentration, the risks from consuming the water may vary. This may be due to differences in exposure (i.e., different people drinking different amounts of water and having different body weights, different exposure frequencies, and different exposure durations) as well as differences in response (e.g., genetic differences in resistance to a chemical dose). Those inherent differences are referred to as variability. Differences among individuals in a population are referred to as inter-individual variability, differences for one individual over time is referred to as intra-individual variability. [EPA 2003]\n\n16. Refers to the observed differences attributable to true heterogeneity or diversity in a population or exposure parameter. Examples include human physiological variation (e.g., natural variation in body weight, height, breathing rate, drinking water intake rate), weather variability, variation in soil types and differences in contaminant concentrations in the environment. Variability is usually not reducible by further measurement of study, but it can be better characterized. [EPA 2004]\n\n17. Intrinsic heterogeneity in a process or parameter. [KIWA 2004]\n\n18. A description of differences among the individual members of a series or population. [FDA 2002]\n\n19. Observed differences attributable to true heterogeneity or diversity in a population or exposure parameter. Variability implies real differences among members of that population. For example, different individuals have different intakes and susceptibility. Differences over time for a given individual are referred to as intra-individual variability. Differences over members of a population at a given time are referred to as inter-individual variability. Variability in microbial risk assessment cannot be reduced but only more precisely characterized. [FAO/WHO 2003b]\n\n20. Inherent natural variation, diversity, and heterogeneity across time and/or space or among individuals within a population.\n\n21. This refers to the observed differences attributable to true heterogeneity or diversity in a parameter. Examples include human physiological variation (e.g., natural variation in body weight, height, breathing rate, drinking water intake rate), weather variability, variation in soil types, and differences in contaminant concentrations in the environment. Variability is usually not reducible by further measurements of study, but it can be better characterized. NRC Definition: Variability refers to true differences in attributes due to heterogeneity or diversity. Variability is usually not reducible by further measurements of study, although it can be better characterized. [USDA/FSIS/2012-001; EPA/100/J12/001]\n\n22. This refers to the observed differences attributable to true heterogeneity or diversity in a parameter. Examples include human physiological variation (e.g., natural variation in body weight, height, breathing rate, drinking water intake rate), weather variability, variation in soil types, and differences in contaminant concentrations in the environment. Variability is usually not reducible by further measurements of study, but it can be better characterized. NRC Definition: Variability refers to true differences in attributes due to heterogeneity or diversity. Variability is usually not reducible by further measurements of study, although it can be better characterized.",
  "subject": "Science and research",
  "references": [
    "Modeling Glossary",
    "Integrated Risk Information System (IRIS) Glossary; EPA 2003",
    "Risk Assessment Glossary",
    "Health & Environmental Research Online (HERO) Glossary",
    "Great Lakes Quality Mgmt Plan Glossary",
    "CADDIS Glossary",
    "Exposure Factors Handbook: Glossary; EPA 1997a",
    "Benchmark Dose Software (BMDS) Glossary of Terms",
    "EPA 2004",
    "FDA 2002",
    "EPA Definitions of Terms Relevant to PRA and References for Further Reading at http://www.epa.gov/oswer/riskassessment/rags3adt/pdf/appendixe.pdf",
    "EPA Guidance on the Development, Evaluation and Application of Environmental Models EPA/100/K-09/003 | March 2009 at http://www.epa.gov/crem/library/cred_guidance_0309.pdf",
    "Thesaurus of Terms Used in Microbial Risk Assessment",
    "40 CFR 702.33 (CFR 2019)",
    "Environmental Sampling and Analytical Methods (ESAM) Program Glossary",
    "USDA/FSIS/2012-001; EPA/100/J12/001"
  ],
  "url": "https://mlchart.com/terminology/environment/variability/"
}