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Frequently-Asked Questions

  • What does statistically significant mean?  -- In epidemiological studies, there is a need to quantify the extent to which random variability could produce results like those observed in a given study....
  • What is a biologic mark of exposure?  -- A biologic marker of exposure is a chemical or its metabolite measured in human body fluids or tissues that can be used to validate human exposure to a hazardous substance.
  • What is a cancer cluster investigation?  -- A cluster study (most often a cancer study) is a descriptive study involving a review of an unusual number, real or perceived, of health events (for example, reports of cancer) grouped together in time...
  • What is a case report or case series?  -- A case report is a descriptive study of a single individual (case report) or small group (case series) in which the possibility of an association between an observed effect and a specific environmental...
  • What is a case-control study?  -- A case-control study is an analytical study which compares individuals who have a specific disease ("cases") with a group of individuals without the disease ("controls")....
  • What is a chemical substance?  -- A chemical substance is a material defined in the Toxic Substances Control Act of 1976 to be any organic or inorganic substance of a particular molecular identity.
  • What is a cohort study?  -- A cohort study is an analytical study in which individuals with differing exposures to a suspected factor are identified and then observed for the occurrence of certain health effects over some period,...
  • What is a community health study and potential challenges of conducting one?  -- A community health study can help suggest a link between an environmental exposure and illness....
  • What is a confounding factor?  -- Epidemiological studies search for the causes of diseases, based on associations with various risk factors that are measured in the study....
  • What is a correlational study?  -- Correlational (sometimes called ecologic) studies explore the statistical connection between disease in different population groups and estimated exposures in groups rather than individuals....
  • What is a cross-sectional study?  -- A cross-sectional study is a descriptive study in which disease and exposure status are measured simultaneously in a given population....
  • What is a descriptive study?  -- Descriptive epidemiologic studies examine differences in disease rates among populations in relation to age, gender, race, and differences in temporal or environmental conditions....
  • What is a Geographic Information System (GIS)?  -- A Geographic Information System (GIS) is computer software mapping technology....
  • What is a hazardous waste?  -- A hazardous waste is a material defined in the Resource Conservation and Recovery Act of 1976 to be in solid, liquid, semisolid, or gaseous form, that "may......
  • What is a health consultation?  -- A health consultation is a written report that provides advice on a specific public health issue related to real or possible human exposure to toxic material....
  • What is a public health assessment?  -- A public health assessment is a written report that reviews available information about hazardous substances at a site and evaluates whether exposure to them might cause any harm to people....
  • What is a site team?  -- The site team is a work group of individuals with environmental, health, and community expertise who can contribute to the public health assessment process....
  • What is a superfund site?  -- A hazardous waste site becomes a Superfund site when it is placed on the U.S....
  • What is a surveillance system?  -- Surveillance systems are generally designed to attain complete or nearly complete coverage of every identified instance of a defined condition in a specific population (for instance, a cancer registry)....
  • What is an analytical study?  -- Analytical epidemiologic studies are most useful for testing an hypothesized association between human exposure and adverse health effects....
  • What is an exposure assessment?  -- Exposure assessment is the process to ascertain the total exposure to individuals from a given source of living or working in a certain area....
  • What is ATSDR?  -- The Agency for Toxic Substances and Disease Registry (ATSDR) is a federal public health agency whose mission is to prevent exposure and adverse human health effects and diminished quality of life associated...
  • What is community involvement?  -- Community involvement is a component of environmental health investigations (public health assessments, exposure assessments, epidemiological studies) which identifies community health concerns and provides...
  • What is environmental community health education?  -- Environmental community health education is aimed at promoting health and providing information and training to a community about hazardous substances that may exist in their community, and exposure and...
  • What is environmental health?  --  Different agencies define "environmental health" in different ways....
  • What is environmental justice?  -- Environmental justice is the fair treatment and meaningful involvement of all people regardless of race, color, national origin, or income with respect to the development, implementation and enforcement...
  • What is epidemiology?  -- Epidemiology is the study of the occurrence and causes of health effects in human populations....
  • What is health professional education?  -- Health professional education in environmental health is aimed an improving the knowledge, skill, and behavior of health professionals concerning taking an exposure history, understanding the geographical...
  • What is risk assessment?  -- The process of assessing the likelihood that a given hazardous material may contribute to a particular disease or ill health....