A B C D E F G H I L M N O P R S T U V Y Z

**AGE-ADJUSTED MORTALITY RATE**. A mortality rate
statistically modified to eliminate the effect of different age distributions in the
different populations.

**AGENT**. A factor, such as a microorganism, chemical
substance, or form of radiation, whose presence, excessive presence, or (in deficiency
diseases) relative absence is essential for the occurrence of a disease.

**AGE-SPECIFIC MORTALITY RATE.** A mortality rate
limited to a particular age group. The numerator is the number of deaths in that age
group; the denominator is the number of persons in that age group in the population.

**ANALYTIC EPIDEMIOLOGY.** The aspect of epidemiology
concerned with the search for health-related causes and effects. Uses comparison groups,
which provide baseline data, to quantify the association between exposures and outcomes,
and test hypotheses about causal relationships.

**ANALYTIC STUDY.** A comparative study intended to
identify and quantify associations, test hypotheses, and identify causes. Two common types
are cohort study and case-control study.

**APPLIED EPIDEMIOLOGY. **The application or practice
of epidemiology to address public health issues.

**ASSOCIATION. **Statistical relationship between two
or more events, characteristics, or other variables.

**ATTACK RATE**. A variant of an incident rate, applied
to a narrowly defined population observed for a limited period of time, such as during an
epidemic.

**ATTRIBUTABLE PROPORTION.** A measure of the public
health impact of a causative factor; proportion of a disease in a group that is exposed to
a particular factor which can be attributed to their exposure to that factor.

**BAR CHART.** A visual display of the size of the
different categories of a variable. Each category or value of the variable is represented
by a bar.

**BIAS.** Deviation of results or inferences from the
truth, or processes leading to such systematic deviation. Any trend in the collection,
analysis, interpretation, publication, or review of data that can lead to conclusions that
are systematically different from the truth.

**BIOLOGIC TRANSMISSION.** The indirect vector-borne
transmission of an infectious agent in which the agent undergoes biologic changes within
the vector before being transmitted to a new host.

**BOX PLOT.** A visual display that summarizes data
using a ``box and whiskers'' format to show the minimum and maximum values (ends of the
whiskers), interquartile range (length of the box), and median (line through the box).

**CARRIER.** A person or animal without apparent
disease who harbors a specific infectious agent and is capable of transmitting the agent
to others. The carrier state may occur in an individual with an infection that is
inapparent throughout its course (known as asymptomatic carrier), or during the incubation
period, convalescence, and postconvalescence of an individual with a clinically
recognizable disease. The carrier state may be of short or long duration (transient
carrier or chronic carrier).

**CASE.** In epidemiology, a countable instance in the
population or study group of a particular disease, health disorder, or condition under
investigation. Sometimes, an individual with the particular disease.

**CASE-CONTROL STUDY. **A type of observational
analytic study. Enrollment into the study is based on presence (``case'') or absence
(``control'') of disease. Characteristics such as previous exposure are then compared
between cases and controls.

**CASE DEFINITION.** A set of standard criteria for
deciding whether a person has a particular disease or health-related condition, by
specifying clinical criteria and limitations on time, place, and person.

**CASE-FATALITY RATE.** The proportion of persons with
a particular condition (cases) who die from that condition. The denominator is the number
of incident cases; the numerator is the number of cause-specific deaths among those cases.

**CAUSE OF DISEASE. **A factor (characteristic,
behavior, event, etc.) that directly influences the occurrence of disease. A reduction of
the factor in the population should lead to a reduction in the occurrence of disease.

**CAUSE-SPECIFIC MORTALITY RATE. **The mortality rate
from a specified cause for a population. The numerator is the number of deaths attributed
to a specific cause during a specified time interval; the denominator is the size of the
population at the midpoint of the time interval.

**CENSUS. **The enumeration of an entire population,
usually with details being recorded on residence, age, sex, occupation, ethnic group,
marital status, birth history, and relationship to head of household.

**CHAIN OF INFECTION.** A process that begins when an
agent leaves its reservoir or host through a portal of exit, and is conveyed by some mode
of transmission, then enters through an appropriate portal of entry to infect a
susceptible host.

**CLASS INTERVAL.** A span of values of a continuous
variable which are grouped into a single category for a frequency distribution of that
variable.

**CLUSTER.** An aggregation of cases of a disease or
other health-related condition, particularly cancer and birth defects, which are closely
grouped in time and place. The number of cases may or may not exceed the expected number;
frequently the expected number is not known.

**COHORT.** A well-defined group of people who have had
a common experience or exposure, who are then followed up for the incidence of new
diseases or events, as in a cohort or prospective study. A group of people born during a
particular period or year is called a birth cohort.

**COHORT STUDY.** A type of observational analytic
study. Enrollment into the study is based on exposure characteristics or membership in a
group. Disease, death, or other health-related outcomes are then ascertained and compared.

**COMMON SOURCE OUTBREAK.** An outbreak that results
from a group of persons being exposed to a common noxious influence, such as an infectious
agent or toxin. If the group is exposed over a relatively brief period of time, so that
all cases occur within one incubation period, then the common source outbreak is further
classified as a point source outbreak. In some common source outbreaks, persons may be
exposed over a period of days, weeks, or longer, with the exposure being either
intermittent or continuous.

**CONFIDENCE INTERVAL.** A range of values for a
variable of interest, e.g., a rate, constructed so that this range has a specified
probability of including the true value of the variable. The specified probability is
called the confidence level, and the end points of the confidence interval are called the
confidence limits.

**CONFIDENCE LIMIT.** The minimum or maximum value of a
confidence interval.

**CONTACT.** Exposure to a source of an infection, or a
person so exposed.

**CONTAGIOUS.** Capable of being transmitted from one
person to another by contact or close proximity.

**CONTINGENCY TABLE.** A two-variable table with
cross-tabulated data.

**CONTROL.** In a case-control study, comparison group
of persons without disease.

**CRUDE MORTALITY RATE.** The mortality rate from all
causes of death for a population.

**CUMULATIVE FREQUENCY.** In a frequency distribution,
the number or proportion of cases or events with a particular value or in a particular
class interval, plus the total number or proportion of cases or events with smaller values
of the variable.

**CUMULATIVE FREQUENCY CURVE.** A plot of the
cumulative frequency rather than the actual frequency for each class interval of a
variable. This type of graph is useful for identifying medians, quartiles, and other
percentiles.

**DEATH-TO-CASE RATIO.** The number of deaths
attributed to a particular disease during a specified time period divided by the number of
new cases of that disease identified during the same time period.

**DEMOGRAPHIC INFORMATION. **The ``person''
characteristics--age, sex, race, and occupation--of descriptive epidemiology used to
characterize the populations at risk.

**DENOMINATOR.** The lower portion of a fraction used
to calculate a rate or ratio. In a rate, the denominator is usually the population (or
population experience, as in person-years, etc.) at risk.

**DEPENDENT VARIABLE.** In a statistical analysis, the
outcome variable(s) or the variable(s) whose values are a function of other variable(s)
(called independent variable(s) in the relationship under study).

**DESCRIPTIVE EPIDEMIOLOGY.** The aspect of
epidemiology concerned with organizing and summarizing health-related data according to
time, place, and person.

**DETERMINANT.** Any factor, whether event,
characteristic, or other definable entity, that brings about change in a health condition,
or in other defined characteristics.

**DIRECT TRANSMISSION.** The immediate transfer of an
agent from a reservoir to a susceptible host by direct contact or droplet spread.

**DISTRIBUTION.** In epidemiology, the frequency and
pattern of health-related characteristics and events in a population. In statistics, the
observed or theoretical frequency of values of a variable.

**DOT PLOT.** A visual display of the actual data
points of a noncontinuous variable.

**DROPLET NUCLEI. **The residue of dried droplets that
may remain suspended in the air for long periods, may be blown over great distances, and
are easily inhaled into the lungs and exhaled.

**DROPLET SPREAD.** The direct transmission of an
infectious agent from a reservoir to a susceptible host by spray with relatively large,
short-ranged aerosols produced by sneezing, coughing, or talking.

**ENDEMIC DISEASE.** The constant presence of a disease
or infectious agent within a given geographic area or population group; may also refer to
the usual prevalence of a given disease within such area or group.

**ENVIRONMENTAL FACTOR.** An extrinsic factor (geology,
climate, insects, sanitation, health services, etc.) which affects the agent and the
opportunity for exposure.

**EPIDEMIC.** The occurrence of more cases of disease
than expected in a given area or among a specific group of people over a particular period
of time.

**EPIDEMIC CURVE. **A histogram that shows the course
of a disease outbreak or epidemic by plotting the number of cases by time of onset.

**EPIDEMIC PERIOD.** A time period when the number of
cases of disease reported is greater than expected.

**EPIDEMIOLOGIC TRIAD.** The traditional model of
infectious disease causation. Includes three components: an external agent, a susceptible
host, and an environment that brings the host and agent together, so that disease occurs.

**EPIDEMIOLOGY.** The study of the distribution and
determinants of health-related states or events in specified populations, and the
application of this study to the control of health problems.

**EVALUATION. **A process that attempts to determine as
systematically and objectively as possible the relevance, effectiveness, and impact of
activities in the light of their objectives.

**EXPERIMENTAL STUDY.** A study in which the
investigator specifies the exposure category for each individual (clinical trial) or
community (community trial), then follows the individuals or community to detect the
effects of the exposure.

**EXPOSED (GROUP). **A group whose members have been
exposed to a supposed cause of disease or health state of interest, or possess a
characteristic that is a determinant of the health outcome of interest.

**FREQUENCY DISTRIBUTION.** A complete summary of the
frequencies of the values or categories of a variable; often displayed in a two column
table: the left column lists the individual values or categories, the right column
indicates the number of observations in each category.

**FREQUENCY POLYGON.** A graph of a frequency
distribution with values of the variable on the x-axis and the number of observations on
the y-axis; data points are plotted at the midpoints of the intervals and are connected
with a straight line.

**GRAPH. **A way to show quantitative data visually,
using a system of coordinates.

**HEALTH. **A state of complete physical, mental, and
social well-being and not merely the absence of disease or infirmity.

**HEALTH INDICATOR.** A measure that reflects, or
indicates, the state of health of persons in a defined population, e.g., the infant
mortality rate.

**HEALTH INFORMATION SYSTEM.** A combination of health
statistics from various sources, used to derive information about health status, health
care, provision and use of services, and impact on health.

**HIGH-RISK GROUP.** A group in the community with an
elevated risk of disease.

**HISTOGRAM. **A graphic representation of the
frequency distribution of a continuous variable. Rectangles are drawn in such a way that
their bases lie on a linear scale representing different intervals, and their heights are
proportional to the frequencies of the values within each of the intervals.

**HOST.** A person or other living organism that can be
infected by an infectious agent under natural conditions.

**HOST FACTOR.** An intrinsic factor (age, race, sex,
behaviors, etc.) which influences an individual's exposure, susceptibility, or response to
a causative agent.

**HYPERENDEMIC DISEASE.** A disease that is constantly
present at a high incidence and/or prevalence rate.

**HYPOTHESIS.** A supposition, arrived at from
observation or reflection, that leads to refutable predictions. Any conjecture cast in a
form that will allow it to be tested and refuted.

**HYPOTHESIS, NULL.** The first step in testing for
statistical significance in which it is assumed that the exposure is not related to
disease.

**HYPOTHESIS, ALTERNATIVE.** The hypothesis, to be
adopted if the null hypothesis proves implausible, in which exposure is associated with
disease.

**IMMUNITY, ACTIVE.** Resistance developed in response
to stimulus by an antigen (infecting agent or vaccine) and usually characterized by the
presence of antibody produced by the host.

**IMMUNITY, HERD.** The resistance of a group to
invasion and spread of an infectious agent, based on the resistance to infection of a high
proportion of individual members of the group. The resistance is a product of the number
susceptible and the probability that those who are susceptible will come into contact with
an infected person.

**IMMUNITY, PASSIVE. **Immunity conferred by an
antibody produced in another host and acquired naturally by an infant from its mother or
artificially by administration of an antibody-containing preparation (antiserum or immune
globulin).

**INCIDENCE RATE. **A measure of the frequency with
which an event, such as a new case of illness, occurs in a population over a period of
time. The denominator is the population at risk; the numerator is the number of new cases
occurring during a given time period.

**INCUBATION PERIOD. **A period of subclinical or
inapparent pathologic changes following exposure, ending with the onset of symptoms of
infectious disease.

**INDEPENDENT VARIABLE.** An exposure, risk factor, or
other characteristic being observed or measured that is hypothesized to influence an event
or manifestation (the dependent variable).

**INDIRECT TRANSMISSION.** The transmission of an agent
carried from a reservoir to a susceptible host by suspended air particles or by animate
(vector) or inanimate (vehicle) intermediaries.

**INDIVIDUAL DATA. **Data that have not been put into a
frequency distribution or rank ordered.

**INFECTIVITY.** The proportion of persons exposed to a
causative agent who become infected by an infectious disease.

**INFERENCE, STATISTICAL.** In statistics, the
development of generalizations from sample data, usually with calculated degrees of
uncertainty.

**INTERQUARTILE RANGE. **The central portion of a
distribution, calculated as the difference between the third quartile and the first
quartile; this range includes about one-half of the observations in the set, leaving
one-quarter of the observations on each side.

**LATENCY PERIOD. **A period of subclinical or
inapparent pathologic changes following exposure, ending with the onset of symptoms of
chronic disease.

**MEAN, ARITHMETIC. **The measure of central location
commonly called the average. It is calculated by adding together all the individual values
in a group of measurements and dividing by the number of values in the group.

**MEAN, GEOMETRIC. **The mean or average of a set of
data measured on a logarithmic scale.

**MEASURE OF ASSOCIATION.** A quantified relationship
between exposure and disease; includes relative risk, rate ratio, odds ratio.

**MEASURE OF CENTRAL LOCATION. **A central value that
best represents a distribution of data. Measures of central location include the mean,
median, and mode. Also called the measure of central tendency.

**MEASURE OF DISPERSION. **A measure of the spread of a
distribution out from its central value. Measures of dispersion used in epidemiology
include the interquartile range, variance, and the standard deviation.

**MEDIAN.** The measure of central location which
divides a set of data into two equal parts.

**MEDICAL SURVEILLANCE.** The monitoring of potentially
exposed individuals to detect early symptoms of disease.

**MIDRANGE.** The halfway point or midpoint in a set of
observations. For most types of data, it is calculated as the sum of the smallest
observation and the largest observation, divided by two. For age data, one is added to the
numerator. The midrange is usually calculated as an intermediate step in determining other
measures.

**MODE.** A measure of central location, the most
frequently occurring value in a set of observations.

**MORBIDITY. **Any departure, subjective or objective,
from a state of physiological or psychological well-being.

**MORTALITY RATE.** A measure of the frequency of
occurrence of death in a defined population during a specified interval of time.

**MORTALITY RATE, INFANT.** A ratio expressing the
number of deaths among children under one year of age reported during a given time period
divided by the number of births reported during the same time period. The infant mortality
rate is usually expressed per 1,000 live births.

**MORTALITY RATE, NEONATAL.** A ratio expressing the
number of deaths among children from birth up to but not including 28 days of age divided
by the number of live births reported during the same time period. The neonatal mortality
rate is usually expressed per 1,000 live births.

**MORTALITY RATE, POSTNEONATAL.** A ratio expressing
the number of deaths among children from 28 days up to but not including 1 year of age
during a given time period divided by the number of lives births reported during the same
time period. The postneonatal mortality rate is usually expressed per 1,000 live births.

**NATURAL HISTORY OF DISEASE. **The temporal course of
disease from onset (inception) to resolution.

**NECESSARY CAUSE.** A causal factor whose presence is
required for the occurrence of the effect (of disease).

**NOMINAL SCALE.** Classification into unordered
qualitative categories; e.g., race, religion, and country of birth as measurements of
individual attributes are purely nominal scales, as there is no inherent order to their
categories.

**NORMAL CURVE.** A bell-shaped curve that results when
a normal distribution is graphed.

**NORMAL DISTRIBUTION.** The symmetrical clustering of
values around a central location. The properties of a normal distribution include the
following: (1) It is a continuous, symmetrical distribution; both tails extend to
infinity; (2) the arithmetic mean, mode, and median are identical; and, (3) its shape is
completely determined by the mean and standard deviation.

**NUMERATOR.** The upper portion of a fraction.

**OBSERVATIONAL STUDY. **Epidemiological study in
situations where nature is allowed to take its course. Changes or differences in one
characteristic are studied in relation to changes or differences in others, without the
intervention of the investigator.

**ODDS RATIO.** A measure of association which
quantifies the relationship between an exposure and health outcome from a comparative
study; also known as the cross-product ratio.

**ORDINAL SCALE. **Classification into ordered
qualitative categories; e.g., social class (I, II, III, etc.), where the values have a
distinct order, but their categories are qualitative in that there is no natural
(numerical) distance between their positive values.

**OUTBREAK. **Synonymous with epidemic. Sometimes the
preferred word, as it may escape sensationalism associated with the word epidemic.
Alternatively, a localized as opposed to generalized epidemic.

**PANDEMIC.** An epidemic occurring over a very wide
area (several countries or continents) and usually affecting a large proportion of the
population.

**PATHOGENICITY.** The proportion of persons infected,
after exposure to a causative agent, who then develop clinical disease.

**PERCENTILE. **The set of numbers from 0 to 100 that
divide a distribution into 100 parts of equal area, or divide a set of ranked data into
100 class intervals with each interval containing 1/100 of the observations. A particular
percentile, say the 5th percentile, is a cut point with 5 percent of the observations
below it and the remaining 95% of the observations above it.

**PERIOD PREVALENCE. **The amount a particular disease
present in a population over a period of time.

**PERSON-TIME RATE.** A measure of the incidence rate
of an event, e.g., a disease or death, in a population at risk over an observed period to
time, that directly incorporates time into the denominator.

**PIE CHART.** A circular chart in which the size of
each ``slice'' is proportional to the frequency of each category of a variable.

**POINT PREVALENCE.** The amount of a particular
disease present in a population at a single point in time.

**POPULATION.** The total number of inhabitants of a
given area or country. In sampling, the population may refer to the units from which the
sample is drawn, not necessarily the total population of people.

**PREDICTIVE VALUE POSITIVE.** A measure of the
predictive value of a reported case or epidemic; the proportion of cases reported by a
surveillance system or classified by a case definition which are true cases.

**PREVALENCE. **The number or proportion of cases or
events or conditions in a given population.

**PREVALENCE RATE.** The proportion of persons in a
population who have a particular disease or attribute at a specified point in time or over
a specified period of time.

**PROPAGATED OUTBREAK. **An outbreak that does not have
a common source, but instead spreads from person to person.

**PROPORTION. **A type of ratio in which the numerator
is included in the denominator. The ratio of a part to the whole, expressed as a ``decimal
fraction'' (e.g., 0.2), as a fraction (1/5), or, loosely, as a percentage (20%).

**PROPORTIONATE MORTALITY. **The proportion of deaths
in a specified population over a period of time attributable to different causes. Each
cause is expressed as a percentage of all deaths, and the sum of the causes must add to
100%. These proportions are not mortality rates, since the denominator is all deaths, not
the population in which the deaths occurred.

**PUBLIC HEALTH SURVEILLANCE.** The systematic
collection, analysis, interpretation, and dissemination of health data on an ongoing
basis, to gain knowledge of the pattern of disease occurrence and potential in a
community, in order to control and prevent disease in the community.

**RACE-SPECIFIC MORTALITY RATE.** A mortality rate
limited to a specified racial group. Both numerator and denominator are limited to the
specified group.

**RANDOM SAMPLE. **A sample derived by selecting
individuals such that each individual has the same probability of selection.

**RANGE.** In statistics, the difference between the
largest and smallest values in a distribution. In common use, the span of values from
smallest to largest.

**RATE. **An expression of the frequency with which an
event occurs in a defined population.

**RATE RATIO.** A comparison of two groups in terms of
incidence rates, person-time rates, or mortality rates.

**RATIO. **The value obtained by dividing one quantity
by another.

**RELATIVE RISK.** A comparison of the risk of some
health-related event such as disease or death in two groups.

**REPRESENTATIVE SAMPLE.** A sample whose
characteristics correspond to those of the original population or reference population.

**RESERVOIR.** The habitat in which an infectious agent
normally lives, grows and multiplies; reservoirs include human reservoirs, animals
reservoirs, and environmental reservoirs.

**RISK. **The probability that an event will occur,
e.g. that an individual will become ill or die within a stated period of time or age.

**RISK FACTOR.** An aspect of personal behavior or
lifestyle, an environmental exposure, or an inborn or inherited characteristic that is
associated with an increased occurrence of disease or other health-related event or
condition.

**RISK RATIO. **A comparison of the risk of some
health-related event such as disease or death in two groups.

**SAMPLE.** A selected subset of a population. A sample
may be random or non-random and it may be representative or non-representative.

**SCATTER DIAGRAM.** A graph in which each dot
represents paired values for two continuous variables, with the x-axis representing one
variable and the y-axis representing the other; used to display the relationship between
the two variables; also called a scattergram.

**SEASONALITY.** Change in physiological status or in
disease occurrence that conforms to a regular seasonal pattern.

**SECONDARY ATTACK RATE. **A measure of the frequency
of new cases of a disease among the contacts of known cases.

**SECULAR TREND.** Changes over a long period of time,
generally years or decades.

**SENSITIVITY.** The ability of a system to detect
epidemics and other changes in disease occurrence. The proportion of persons with disease
who are correctly identified by a screening test or case definition as having disease.

**SENTINEL SURVEILLANCE.** A surveillance system in
which a pre-arranged sample of reporting sources agrees to report all cases of one or more
notifiable conditions.

**SEX-SPECIFIC MORTALITY RATE.** A mortality rate among
either males or females.

**SKEWED.** A distribution that is asymmetrical.

**SPECIFICITY.** The proportion of persons without
disease who are correctly identified by a screening test or case definition as not having
disease.

**SPORADIC.** A disease that occurs infrequently and
irregularly.

**SPOT MAP. **A map that indicates the location of each
case of a rare disease or outbreak by a place that is potentially relevant to the health
event being investigated, such as where each case lived or worked.

**STANDARD DEVIATION.** The most widely used measure of
dispersion of a frequency distribution, equal to the positive square root of the variance.

**STANDARD ERROR (OF THE MEAN). **The standard
deviation of a theoretical distribution of sample means about the true population mean.

**SUFFICIENT CAUSE. **A causal factor or collection of
factors whose presence is always followed by the occurrence of the effect (of disease).

**SURVEILLANCE.** see PUBLIC HEALTH SURVEILLANCE

**SURVIVAL CURVE.** A curve that starts at 100% of the
study population and shows the percentage of the population still surviving at successive
times for as long as information is available. May be applied not only to survival as
such, but also to the persistence of freedom from a disease, or complication or some other
endpoint.

**TABLE. **A set of data arranged in rows and columns.

**TABLE SHELL. **A table that is complete except for
the data.

**TRANSMISSION OF INFECTION.** Any mode or mechanism by
which an infectious agent is spread through the environment or to another person.

**TREND. **A long-term movement or change in frequency,
usually upwards or downwards.

**UNIVERSAL PRECAUTIONS.** Recommendations issued by
CDC to minimize the risk of transmission of bloodborne pathogens, particularly HIV and
HBV, by health care and public safety workers. Barrier precautions are to be used to
prevent exposure to blood and certain body fluids of all patients.

**VALIDITY.** The degree to which a measurement
actually measures or detects what it is supposed to measure.

**VARIABLE.** Any characteristic or attribute that can
be measured.

**VARIANCE. **A measure of the dispersion shown by a
set of observations, defined by the sum of the squares of deviations from the mean,
divided by the number of degrees of freedom in the set of observations.

**VECTOR. **An animate intermediary in the indirect
transmission of an agent that carries the agent from a reservoir to a susceptible host.

**VEHICLE.** An inanimate intermediary in the indirect
transmission of an agent that carries the agent from a reservoir to a susceptible host.

**VIRULENCE. **The proportion of persons with clinical
disease, who after becoming infected, become severely ill or die.

**VITAL STATISTICS.** Systematically tabulated
information about births, marriages, divorces, and deaths, based on registration of these
vital events.

**YEARS OF POTENTIAL LIFE LOST. **A measure of the
impact of premature mortality on a population, calculated as the sum of the differences
between some predetermined minimum or desired life span and the age of death for
individuals who died earlier than that predetermined age.

**ZOONOSES. **An infectious disease that is
transmissible under normal conditions from animals to humans.

The definitions given are valid as they are used in this publication but different definitions may be used in other contexts. A Dictionary of Epidemiology, Second Edition, edited by J.M. Last for the International Epidemiological Association and published by Oxford University Press, 1988, was helpful in providing a number of the definitions.

Copyright ©2000-2016 Geigle Safety Group, Inc. All rights reserved. Federal copyright prohibits unauthorized reproduction by any means without permission. Students may reproduce materials for personal study. Disclaimer: This material is for training purposes only to inform the reader of occupational safety and health best practices and general compliance requirement and is not a substitute for provisions of the OSH Act of 1970 or any governmental regulatory agency. CertiSafety is a division of Geigle Safety Group, Inc., and is not connected or affiliated with the U.S. Department of Labor (DOL), or the Occupational Safety and Health Administration (OSHA).