Analysis of covariance- A statistical analysis in which dependent
variable means are adjusted for whatever differences there are between the groups on the covariate.
Attrition (drop-out)- Those who did not complete the post-intervention
measure. Individuals often drop out of programs and are not available for all evaluation activities.
When specific types of people drop out of the program, those individuals who have the most or least to gain
from a program or those in one group, the results of evaluation may be uninterpretable.
Baseline- Measures of the dependent variable taken prior to the
introduction of the treatment in a time-series experimental design and used as the standard of comparison.
Baseline interview- Information gathered at the beginning of a study from
which variations found in the study are measured. A known value or quantity with which an unknown is
compared. In a single-subject design, the subject’s behavior during a control period before introduction of
the experimental manipulation.
Behavioral intervention- Behavioral interventions aim to change
individual behaviors only, without explicit or direct attempts to change the norms (social or peer) of the
community, e.g., geographically defined area, or the target population, e.g., drug users or men having sex
with men. Typical example of these interventions include health education, risk reduction counseling, and
other individual-level interventions.
Behavioral science- An area of social sciences research that examines
individuals’ behaviors in depth; it explores what people do and why they do it.
Capacity building- One or more activities that contribute to an increase
in the quality, quantity, and efficiency of program services and the infrastructure and organizational
systems that support these program services. In the case of HIV prevention capacity building, the
activities are associated with the core competencies of an organization that contribute to its ability to
develop and implement an effective HIV prevention intervention and to sustain the infrastructure and resource
base necessary to support and maintain the intervention.
Case management- A system for assuring effective delivery of services and
maintaining access to resources for individuals with multiple, changing service needs.
Case study- A non-experimental design that provides a detailed analysis
of an individual program in which no attempt is made to control potentially causal variables and the
focus is on description of activities. Case studies may be performed on several programs simultaneously
to allow qualitative comparisons of certain aspects of the programs.
Client level data- Data that derive from individual clients.
Close-ended questions- Questions in an interview or survey format that
provide a limited set of predefined alterative responses; for example, a survey might ask respondents
if they are receiving case management services, and if they say yes, ask “About how often have you been
in contact with your case manager for services during the past six months, either in person or by
telephone?” and provide the following response options: Once a week or more, two to three times a
month, approximately once a month, three to five times, one to two times, not at all.
Community-Level Interventions (CLI)- Programs designed to reach a defined
community (geographic or an identified subgroup), to increase community support of the
behaviors known to reduce the risk for HIV infection and transmission, by working with the
social norms or shared beliefs and values held by members of the community. CLI aim to reduce risky
behaviors by changing attitudes, norms, and practices through community mobilization and
organization, and community-wide events.
Community mobilization- Community mobilization is the process by which
community citizens take an active role in defining, prioritizing, and addressing issues in their
community. This process focuses on identifying and activating the skills and resources of residents and
organizations while developing linkages and relationships within and beyond the community for the purpose of
expanding the current scope and effectiveness of HIV/STD prevention.
Community Planning Groups (CPGs)- Groups responsible for conducting HIV
Prevention Community Planning; CPGs are composed of community representatives,
scientists and other technical experts, and staff of non-governmental organizations, and departments of
health, education, and substance abuse prevention.
Comparison group- Individuals whose characteristics (such as
race/ethnicity, gender, and age) are similar to those of the program participants. These individuals may not
receive an services, or they may receive a different set of services, activities, or products. As part of the
evaluation process, the experimental (or treatment) group and the comparison group are assessed to
determine which type of services, activities, or products provided by your program produced the
expected changes.
Confounding variables- Things that compete with the ability to say that a
change occurred and that the change was due to the intervention, e.g., Magic Johnson’s announcement of
his infection.
Contemplation- One of the stages of the Stages of Change behavioral
theory; person is aware that a problem exists, is seriously thinking about overcoming it, but has not yet
made a commitment to take action.
Control group- A group of individuals whose characteristics (such as
race/ethnicity, gender, and age) are similar to those of your program participants, but do not receive the
program (services, products, or activities) you are evaluating. Participants are randomly assigned to either
the treatment (or program) group and the control group. A control group is used to assess the effect of
your program on participants as compared to similar individuals not receiving the services,
products, or activities you are evaluating. The same information is collected for people in the control group
as in the experimental group.
Correlation- A statistical measure of the degree of
relationship/association between variables.
Cost effectiveness analysis- A type of analysis that involves comparing
the relative costs of operating a program with the extent to which the program met its goals and
objectives; for example a program to reduce HIV transmission would estimate the dollars that had to be
expended for prevention efforts compared to dollars expended for HIV related treatment and services.
Counseling and testing- The voluntary process of client-centered,
interactive information sharing in which an individual is made aware of the basic information about HIV/AIDS,
testing procedures, how to prevent the transmission and acquisition of HIV infection, and given
tailored support on how to adapt this information to their life.
Counseling, Testing, Referral, and Partner Notification- CTRPN refers to
voluntary HIV/AIDS counseling and testing, referral to appropriate medical and social services,
and anonymous or confidential partner notification of sex or needle-sharing partners by health
department staff when accompanied by testing; includes pre-test counseling, for example, when it is
clear that testing is being offered as an option for the individual to consider.
Cross-sectional study- A cross-section is a random sample of a
population, and a cross-sectional study examines this sample at one point in time. Successive cross-sectional
studies can be used as a substitute for a longitudinal study.
Cultural competence- Capacity and skill to function effectively in
environments that are culturally diverse and are composed of distinct elements and qualities.
Culture- The learned patterns of behavior, though, and traits
characteristic of large, autonomous or semi-autonomous, human social groups. These patterns prescribe the acceptable
values, norms, attitudes, social roles and statuses, etiquette, interpersonal and familial
relationships, and personal conduct of the members of the culture. They also define the behavior expected
of other people. Culture is expressed and reinforced through shared language, group identity,
religion/belief system, folklore, social and legal institutions, traditions, customs, history, and
arts.
Data- Specific information or facts that are collected. A data element is
usually a discrete or single measure. Examples of client-level data elements are sex, race/ethnicity, age,
and neighborhood.
Data analysis- The process of systematically applying statistical and
logical techniques to describe, summarize, and compare data collected.
Data system- A systematic structure that contains and tracks data.
Database - An accumulation of information that has been systematically
organized for easy access and analysis. Databases are typically computerized.
Demographics- The statistical characteristics of human populations such
as age, race, ethnicity, and sex that can provide insight into the development, culture, and sex specific
issues that the intervention will need to account for.
Dependent variable- A variable that is a consequence of or dependent on
an antecedent (independent) variable; also called the outcome or effect variable.
Determinants of behavior- The external and internal factors that
determine or influence individuals’ actions.
Drop-off site - Sites that volunteer to distribute HIV prevention
materials. Typically outreach workers keep these sites supplied.
Efficiency analysis- Determining whether particular characteristics of
the clients or the program are associated with different levels of outcomes.
Epidemic- A disease that spreads rapidly through a demographic segment of
the human population, such as everyone in a given geographic area; a military base, or similar
population unit; or everyone of a certain age or sex, such as the children or women of a region. Epidemic
diseases can be spread from person to person or from a contaminated source such as food or water.
Epidemiologic profile- A description of the current status, distribution,
and impact of an infectious disease or other health-related condition in a specified geographic area.
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.
Evaluability assessment- A study to determine if it is possible to
evaluate a program or other activity. Evidence basis- A judgement about the extent to which an intervention is
or is not supported by scientific evidence.
Experimental design- The most rigorous and definitive approach to
research and evaluation that allows the researcher or evaluator to accurately measure outcomes and
determine cause of the outcomes. It includes random assignment to treatment and control groups and
pre- and post-intervention measurements.
Experimental group- Also called a treatment group, an experimental group
is composed of individuals receiving the services, products, or activities (interventions) that you are
evaluating.
External validity- The extent to which study results are representative
of or generalizable to other populations and/or other settings.
Fidelity- Accuracy; the exact adherence to established protocols,
procedures, and content in implementation or replication of a program.
Fixed-site outreach- Outreach activities conducted at a specific place,
e.g., setting up a table at a corner or working out of a mobile van or store front.
Forced-choice question- Type of question often used in a survey
questionnaire, in which the person responding is expected to choose from a list of predetermined responses.
Formative evaluation- Evaluation undertaken during the design and
pre-testing of programs to guide the design process. Emphasizes questions related to how the program is
operating. Used to assist planners, managers and staff to develop a new program or improve an on-going
program.
Frequency indicators- Used to measure how often behaviors or other events
occur.
Generalizability- The extent to which findings or conclusions from a
sample can be assumed to be true for the entire population from which the sample was drawn; findings can
be generalized only when the sampling procedure and the data meet certain methodological standards.
Group-Level Interventions (GLI)- Health education and risk-reduction
counseling that shifts the delivery of service from the individual to groups of varying sizes. Uses peer
and non-peer models involving a wide-range of skills, information, education, and support.
Goals- Broad aims/statements that describe what the proposed project
hopes to accomplish. Goals are not time-phased.
HIV Prevention Community Planning- The cyclical, evidence-based planning
process in which authority for identifying priorities for funding HIV prevention programs is
vested in one or more planning groups in a state or local health department that receives HIV prevention
funds from CDC.
Health Communications/Public Information (HC/PI)- The delivery of planned
HIV/AIDS prevention messages through one or more channels to target audiences that are
designed to build general support for safe behavior, support personal risk-reduction efforts,
and/or inform persons at risk for infection how to obtain specific services. Examples include: electronic
media, print media, hotline, clearinghouse, presentations/lectures.
Health Education and Risk Reduction Interventions (HE/RR)- Organized
efforts to reach persons at increased risk of becoming HIV-infected or, if already infected,
of transmitting the virus to others, with the goal of reducing the risk of these events occurring;
activities range from individual case management to broad community-based interventions.
Human subject- A living individual about whom an investigator (whether
professional or student) conducting research obtains data through intervention or interaction with the
individual, or identifiable private information. Research with human subjects requires an informed
consent, adequate provisions to minimize risk to the individual, and procedures to protect the privacy and
confidentiality of all participants.
IDU- Injection drug user; people who are at risk for HIV infection
through the use of equipment used to inject drugs, e.g., syringes, needles, cookers, spoons, etc.
Impact evaluation- The assessment of the effects of an intervention
beyond the outcomes on individuals targeted by the intervention, e.g., the cumulative effect of HIV
prevention activities in a jurisdiction.
Implementation- To put into effect according to or by means of a definite
plan or procedure, e.g., collecting information about the interventions identified in the HIV
prevention comprehensive plan.
Incidence- The number of new cases of a disease that occur in a specified
population during a specified time period.
Independent variable- A variable that is antecedent to the dependent
variable; also called the experimental or treatment variable.
Individual-Level Interventions (ILI)- Health education and risk-reduction
counseling provided to one individual at a time. ILIs assist clients in making plans for individual
behavior change and ongoing appraisals of their own behavior. These interventions also facilitate
linkages to services in both clinic and community settings, e.g., substance abuse treatment settings, in support
of behaviors and practices that prevent transmission of HIV, and they help clients make plans to obtain
these services.
Informed consent- The permission granted by a participant in a research
study after he/she has received comprehensive information about the study. This is a statement of
trust between the institution performing the research procedure and the person on whom the research
procedures are to be performed.
Internal validity- The extent to which an observed effect can be linked
to the intervention and not to other independent causes. No statement can be made about the external
generalizability of effects without first stringently demonstrating that the intervention was responsible
for the observed effects.
Intervals- In a Likert-type scale, the number of points or time interval
between measurements.
Intervention- An intervention is a specific activity (or set of related
activities) intended to bring about HIV risk reduction in a particular target population using a common strategy
of delivering the prevention message. An intervention has distinct process and outcome objectives and a
protocol outlining the steps for implementation.
Intervention plan- Refers to a description of a planned intervention
strategy for a target population.
Justification- A judgement about whether the intervention plan does or
does not explain how the intervention will lead to the specified outcomes.
Likert-type scale - A Likert-type scale has a set of intervals assumed to
be equal, with extremes anchored by opposites, e.g., strongly disagree/strongly agree.
Linkage- The connection between the comprehensive HIV prevention plan and
resource allocation in order to determine if the resources allocated in the previous year (meaning
the year that has just ended) corresponded with recommendations in the plan from the previous year.
Longitudinal method- A developmental research method in which the same
persons are observed repeatedly over time, usually at regular intervals; conceptually similar to a
repeated measures design.
MSM- Men who have sex with men. Men who report sexual contact with other
men, e.g., homosexual contact, or men who report sexual contact with both men and women, e.g.,
bisexual contact.
MSM/IDU- Men who report both sexual contact with other men and injection
drug use.
Mass media- The use of print, radio, and television, to communicate with
specific populations. It includes public service announcements, news broadcasts, infomercials,
magazines, newspapers, billboards, etc., which reach a large-scale audience in a short period of
time.
Matched- Pairs of subjects are matched on the basis of their similarities
on one or more variables, and one member of the pair is assigned to the experimental group and the other to
the control group.
Maturation- Refers to any naturally-occurring trend, cycle, or growth
that may confound the intervention effect.
Methodology- A plan that defines outcome measures, the choice of a
research design, sampling, sample size, and choice of data systems.
Monitoring- Routine documentation of characteristics of the people
served, the services that were provided, and the resources used to provide those services.
Multiple-choice items - Referring to a survey or questionnaire, items
wherein an incomplete statement or item root is presented and the client selects from several responses the
response that would best complete it.
Needs assessment- The process of obtaining and analyzing information from
a variety of sources in order to determine the needs of a particular client, population, or
community.
Nominal scale- A level of data in which numbers are assigned to objects
or events for identification purposes. There is no quantitative relationship implied. Example: Centers,
regions of the country, political party.
Non-Experimental Design - Does not include random assignment or a control
group and asserts little or no control over factors that may confound interpretation of an observed
effect.
Objectives- Specific statements which describe what you plan to do with
your proposed program within a given period.
Open-ended questions- Questions in an interview or survey format that
allow those responding to answer as they choose, rather than having to select one of a limited set of
predefined alternative responses.
Ordinal scale- A scale that arranges and describes things in rank order.
Assumes that some things are greater than or less than others, e.g., class rankings, 1-5 scale.
Outcome evaluation- Outcome evaluation entails the application of
rigorous methods to assess whether the prevention program has an effect on the predetermined set of
goals; the use of rigorous methods allows one to rule out factors that might otherwise appear
responsible for the changes seen; for example outcome evaluation determines whether a particular intervention
had a desired effect on the targeted population’s behavior; whether the intervention provided made a
difference in knowledge, skills, attitudes, beliefs, behaviors, or health outcomes.
Outcome monitoring- Outcome monitoring refers to procedures for assessing
whether providers are meeting the outcome objectives that they set for themselves and efforts to
track the programs of clients in a program based upon outcome measures set forth in program goals. In many
cases - especially for individual and group level counseling interventions - this may simply require
administering a brief questionnaire before the intervention begins and then again after it’s
finished.
Outcome objectives - The overall intended effects of the intervention,
specifying its purpose and mission. These might included increasing knowledge about HIV, changing
risk-related behaviors, promoting community norms for safer sex, or reducing HIV transmission.
Outreach- HIV/AIDS educational interventions generally conducted by peer
or paraprofessional educators face-to-face with high-risk individuals in the clients’
neighborhoods or other areas where clients’ typically congregate. Usually includes distribution of condoms,
bleach, sexual responsibility kits, and educational materials.
Paired (or matched) t-test- A simple statistical test used when you have
two scores from the same individual, such as when collecting pre- and post-intervention data in
outcome monitoring.
Partner Counseling and Referral Services (PCRS)- A systematic approach to
notifying sex and needle-sharing partners of HIV+ persons of their possible exposure to HIV so
they can avoid infection or, if already infected, can prevent transmission to others. PCRS helps
partners gain earlier access to individualized counseling, HIV testing, medical evaluation, treatment, and
other prevention services.
Pilot test- A trial run with a few subjects to assess the appropriateness
and practicability of the procedures and data collecting instruments.
Policy intervention- Policy interventions aim to change/influence
policies that serve as barriers to behavior change. These interventions include, for example, decisions such as
those that permit advertising and social marketing of condoms, allow for pharmacy sales of
needles, and decriminalize prostitution.
Population- A population is any entire collection of people, animals,
plants or things from which data may be collected.
Precode- Means that a certain number or letter (a data entry code) is
printed on the instrument near each response that clients can choose. To simplify data entry.
Pre-contemplation- A stage of the Stages of Change behavioral
theory in which people have little or no intention to take action in the foreseeable future, usually measured as
the next six months.
Pre- and post design- An evaluation design in which a single program or
group is measured prior to program implementation and again after the end of the program.
Pretest- Test of planned public information strategies, messages,
materials or measurement tools before completion or release to allow for feedback and revision to help
assure effectiveness.
Prevalence- The total number of persons living with a specific disease or
condition during a given time period.
Prevention Case Management (PCM) - Client-centered HIV prevention
activity with the fundamental goal of promoting the adoption of HIV risk-reduction behaviors by
clients with multiple, complex problems and risk-reduction needs; a hybrid of HIV risk-reduction
counseling and traditional case management that provides intensive, ongoing, and individualized
prevention counseling, support, and service brokerage.
Process evaluation- A descriptive assessment of the implementation of
program activities; what was done, to whom, and how, when, and where, e.g., assessing such things as an
interventions conformity to program design, how it was implemented, and the extent to which it reaches
the intended audience.
Process monitoring- The collection of data to describe and assess
intervention implementation; for example routine documentation of characteristics describing the target
population served, the services that were provided, and the resources used to deliver those services.
Process objectives- Process objectives describe the specific intervention
activities, the projected level of effort needed to carry them out, the people responsible for carrying them
out, and when they will be completed.
Program - A program is an organized effort to attain a set of
predetermined goals; a program is a distinction often used by an agency to describe a related set of
interventions serving a particular population.
Program evaluation- The systematic assessment of the means and ends of
some or all of the action program stages, including program planning, implementation, and outcomes, in
order to determine the value of and to improve the program.
Program level data- Data that derive from individual programs.
Public health surveillance- An ongoing, systematic process of collecting,
analyzing and using data on specific health conditions and diseases, in order to monitor these health
problems, such as the Centers for Disease Control and Prevention’s (CDC) surveillance system for AIDS.
Qualitative data- Data presented in narrative form that generally are not
expressed numerically, such as the information collected from focus groups or key informant interviews.
Quantitative data- Data presented in numerical terms, such as survey data
and data from epidemiologic reports.
Quasi-experimental design- Includes the establishment of an experimental
group and a comparison group by methods other than random assignment. Results from this design may
yield interpretable and supportive evidence of intervention effects.
Random assignment- A method of assigning subjects to two or more groups
by chance. Randomization serves two principle functions; the first to draw samples that
are representative of a known population, and the second is to have groups that are comparable to
each other within acceptable statistical limits.
Random sampling- Random sampling is a sampling technique where a group of
subjects (a sample) is selected for study from a large group (a population). Each individual is
chosen entirely by chance and each member of the population has a known, and theoretically equal, chance of
being included in the sample.
Referral- A process by which an individual or client who has a need is
connected with a provider who can serve that need (usually in a different agency); for example individuals
with high risk behaviors and those infected with HIV are guided towards prevention, psychosocial, and
medical resources needed to meet their primary and secondary HIV prevention needs.
Relevance- The extent to which an intervention plan addresses the needs
of affected populations in the jurisdiction and of other community stakeholders. As described in the CDC
Guidance, relevance is the extent to which the population targeted in the intervention plan is
consistent with the target population in the comprehensive HIV prevention plan.
Reliability- The consistency of a measure or question, in obtaining very
similar or identical results when used repeatedly; for example, if a test was done on the same blood
sample several times, it would be reliable if it generated the same results each time.
Representative- The term used to indicate that a sample is similar to the
population from which it was drawn, and therefore can be used to draw conclusions about that population.
Research design- A plan that defines the number and type of variables to
be studied and assesses their relationship to one another using well-developed principles of
scientific inquiry.
Risk behavior- Behavior or other factor that places a person at risk for
disease; for HIV/AIDS, includes such factors as sharing of injection drug use equipment, unprotected
male-to-male sexual contact, commercial sex work without the use of condoms.
Sample- A group of subjects selected from a total population or universe
with the expectation that studying the group will provide important information about the total
population.
Sampling frame- The list from which the sample population is drawn, i.e.,
the telephone directory is often used for general population surveys.
Sample size- The number of people from whom data are collected.
Scientific soundness - The application of behavioral and social science
theories developed or adapted by the provider agency or agreement of principles of a program with
accepted scientific findings or theories.
Secondary source data- Existing information that was collected by someone
else, but which you can analyze or re-analyze and use. Such data may be in “raw” (unanalyzed) or
analyzed form.
Self-efficacy- Belief in one’s ability to perform the desired behavior.
Semi-structured questionnaires- Referring to questionnaires, combine
structured questions with open-ended questions.
Seroprevalence- HIV seroprevalence refers to the number of persons in a
population who test HIV+ based on serology (blood serum) specimens; often presented as a percent of
the total specimens tested or as a ratio per 1,000 persons tested.
Seroprevalence reports- Reports which provide information about the
percent or rate of people in specific testing groups and populations who have tested positive for HIV.
Stakeholders (federal, state and local community)- Those who have an
interest in and can affect implementation of an intervention or program; key players; influentials.
Statistical significance- A measure of whether an observed difference or
relationship is larger or smaller than would be expected to occur by chance alone; statistical results
are often considered to be significant if there is less than a 5% chance- 5 out of 100- that they would
have occurred by chance alone.
Stratified random sample- A random sample drawn after dividing the
population being studied into several subgroups or strata based on significant characteristics; sub-samples
are then drawn separately from each of the strata; for example, the population of a community might be
stratified by race/ethnicity before random sampling.
Street outreach- HIV/AIDS educational interventions generally conducted
by peer or paraprofessional educators face-to-face with high-risk individuals in the
clients’ neighborhoods or other areas where clients’ typically congregate. Usually includes distribution of
condoms, bleach, sexual responsibility kits, and educational materials.
Structural Intervention- Interventions designed to remove barriers and
incorporate facilitators of an individual’s HIV prevention behaviors. These barriers or facilitators include
physical, social, cultural, organizational, community, economic, legal, or policy circumstances or
actions that directly or indirectly affect an individual’s ability to avoid exposure to HIV.
Structured survey/questionnaire - Refers to questionnaires or surveys
that are pre-determined and standardized. They include close-ended responses that are easily quantifiable
and typically pre-coded to facilitate the transfer of data to the computer.
Summative evaluation- Evaluation designed to present conclusions about
the merit or worth of an intervention and recommendations about whether it should be retained,
altered, or eliminated.
Sufficiency of the service plan- In reference to the CDC’s evaluation
guidance, the SSP provides details about whether the resources and operational plan for the intervention
will allow it to be executed given its current context within the jurisdiction.
Surveillance- The ongoing and systematic collection, analysis, and
interpretation of data about a disease or health condition. As part of a surveillance system to monitor the
HIV epidemic in the United States, the Centers for Disease Control and Prevention (CDC), in
collaboration with state and local health departments, other federal agencies, blood collection agencies, and
medical research institutions, conducts standardized HIV seroprevalence surveys in designated subgroups of
the U.S. population. Collecting blood samples for the purpose of surveillance is called
serosurveillance.
Surveillance report- Reports providing information on the number of
reported AIDS and HIV cases nationally and for specific locations and subpopulations; the Centers for
Disease Control and Prevention (CDC) issues such a report twice a year, providing both cumulative
cases and new cases reported during specific time periods.
Target populations- Groups of people who are to be reached through some
action or intervention. In HIV prevention community planning, refers to populations that are the focus
of HIV prevention efforts due to high rates of HIV infection, usually defined based on a review of the
HIV epidemiologic profile, and high levels of risky behavior. Groups often defined based on a
combination of characteristics such as race or ethnicity, age, gender, risk factor/behavior, and geographic
location.
Technical assistance- The delivery of expert programmatic, scientific and
technical support to organizations and communities in the design, implementation and evaluation of
HIV prevention interventions and programs.
Time-series design- A special case of the pre-post design in which
measurement are taken repeatedly over time, before, during and after the program.
Transmission categories- In describing HIV/AIDS cases, same as exposure
categories; how an individual may have been exposed to HIV, such as injecting drug use, men who
have sex with men, and heterosexual contact.
Unit of assignment- The unit assigned to study condition. For behavioral
and social science, units of assignment can be individuals, social groups, facilities/sites, or
communities. Unit of analysis should be the same as unit of assignment.
Universe- The total population from which a sample is drawn.
Validity- The extent to which a survey question or other measurement
instrument actually measures what it is supposed to measure; for example, a question that asks young
adults how often they use a condom is valid if it accurately measures their actual level of condom use.
Variable- A characteristic of finding that can change or vary among
different people or in the same person over time; for example, race or ethnicity varies among individuals,
and income varies for the same individual over time.
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