advance research exam 2

what is the definition of a sample

A subset of elements from the larger population.

what is the definition of a population

The entire set of elements (e.g., individuals, cities, states, countries, prisons, schools) in which we are interested.

what is the definition of an element

The individual members of the population whose characteristics are to be measured.

what is the definition of sampling frame?

A list from which the elements of the population are selected

what does generalizability mean

external validity

generalizability has two subsets, which are?

sample and cross population

what is sample generalizability

Does this sample, reflect that population

what is cross population generalizability

Would we find these same results at different times, different populations, and at different settings?

What happens if there is a large sampling error?

the sample is less generalizable to the population

what is probability sampling

Sampling methods that rely on a random, or chance, selection method so that the probability of selection of population elements is known.

what are the four probability sampling methods

simple random, systematic, stratified, and multistage cluster

define simple random sampling

every sample element is selected only on the basis of chance through a random process.

define systematic sampling

sample elements are selected from a list or from sequential files, with every nth element being selected after the first element is selected randomly within the first interval.

define proportionate stratified sampling

elements are selected from strata in exact proportion to their representation in the population

define disproportionate stratified sampling

elements are selected from strata in different proportions from those that appear in the population.

define multistage cluster sampling

elements are selected in two or more stages, with the first stage being the random selection of naturally occurring clusters and the last stage being the random selection of multilevel elements within clusters.

what sampling concern occurs with random sampling?

sampling error: difference between the characteristics of a sample and the characteristics of the population from which it was selected

what sampling concern occurs with systematic sampling

sampling bias: selection bias

what is nonprobability sampling

Sampling methods in which the probability of selection of population elements is unknown.

what are the four nonprobability sampling methods

availability, quota, purposive, and snowballing

what is availability sample

elements are selected on the basis of convenience

what is a quota sample

elements are selected to ensure that the sample represents certain characteristics in proportion to their prevalence in the population

what is a purposive sample

elements are selected for a purpose, usually because of their unique position. Sometimes referred to as judgment sampling

what is a snowball sample?

elements are selected as they are identified by successive informants or interviewees

define a sample statistic

value of a … , such as a mean, computed from sample data.

define a population parameter

the value of a statistic, such as a mean, computed using the data for the entire population

define nomothetic causal explanation

involving the belief that variation in an independent variable will be followed by variation in the dependent variable, when all other things are equal

define idiographic causal explanation

identifies the concrete, individual sequence of events, thoughts, or actions that resulted in a particular outcome for a particular individual or that led to a particular event; may be termed an individualist or historicist explanation

what are the conditions necessary for determining causality

• association

• time order

• nonspuriousness

define association

Variation in one variable is related to variation in another variable as a condition to determine causality

define time order

the variation in the independent variable must come before variation in the dependent variable

define nonspuriousness

A relationship that exists between two variables that is not due to variation in a third variable

define mechanism

A discernible process that creates a causal connection between two variables.

define contextual effect

A relationship between variables that varies between geographic units or other contexts

define cross-sectional research

Studies in which data are collected at only one point in time.

define longitudinal research

Studies in which data are collected that can be ordered in time; also defined as research in which data are collected at two or more points in time

define repeated cross sectional designs

Longitudinal studies in which data are collected at two or more points in time from different samples of the same population

define fixed-sample panel designs

Longitudinal studies in which data are collected from the same individuals at two or more points in time

define event-based designs

Longitudinal studies in which data are collected at two or more points in time from individuals in a cohort

define intervening variables

influenced by an independent variable and, in turn, influence variation in a dependent variable, thus helping to explain the relationship between the independent and dependent variables

define units of observation

The cases about which measures actually are obtained in a sample.

define ecological fallacy

An error in reasoning in which incorrect conclusions about individual-level processes are drawn from group-level data

define reductionist fallacy

An error in reasoning that occurs when incorrect conclusions about group-level processes are based on individual-level data

what is the idiographic approach?

concerned with understanding the subject experiences and personal characteristics

what is the nomothetic approach?

establish general laws of behavior that apply to large groups of people

define the experimental group

the group of subjects that receives the treatment or experimental manipulation.

define the control group

The group of subjects who are either exposed to a different treatment than the other group or who receive no treatment at all

define random assignment

A procedure by which each experimental and control group subject is placed in a group randomly

define quasi-experimental designs

Research designs in which there is a comparison group that is comparable to the experimental group in critical ways, but subjects are not randomly assigned to the comparison and experimental groups

define nonequivalent control group designs

have experimental and comparison groups designated before the treatment occurs that are not created by random assignment.

define before and after designs

have a pretest and posttest but no comparison group. In other words, the subjects exposed to the treatment serve, at an earlier time, as their own controls.

what are the threats to internal validity

• selection bias

• endogenous change

• external threats/history events

• contamination

• treatment misidentification

• mortality

define selection bias

when characteristics of the experimental and comparison group subjects differ

define endogenous change

when the subjects develop or change during the experiment as part of an ongoing process independent of the experimental treatment

ex: maturation, regression toward the mean (were to intentionally recruit someone extremely high or low on a certain characteristic)

define external threats/history events

when something occurs during the experiment, other than the treatment, that influences outcome scores

define contamination

when either the experimental group or the comparison group is aware of the other group and is influenced in the posttest as a result

define treatment misidentification

when variation in the independent variable is associated with variation in the observed outcome, but the change occurs through a process that the researcher has not identified

define mortality

When people in your treatment group drop out faster than people in the control group

in a correlation study

we look for a relationship between two variables that are outside of our control

in a true experiment

we manipulate one variable (IV) to see how this affects some other variable (DV)

in a quasi-experiment

we look at the effect of a variable that cannot (or should not) be manipulated using pre/post and/or comparison groups

evaluative research assesses the effectiveness of

• Program

• Policies

• Interventions

• Criminal justice reforms

types of evaluations

• needs assessment

• process assessment

• outcome/impact assessment

define needs assessment

that attempts to determine the needs of some population that might be met with a social program

define process assessment

that investigates the process of service delivery

define outcome/impact assessment

Analysis of the extent to which a treatment or other service has the intended effect