What is assignment at random?Random assignment of subjects to experimental and control groups.
What is a case study design?A comprehensive and in-depth study of a single case or several cases. A non-experimental design in which the investigator has little control over events.
What is a classical experimental design?An experiment with the random assignment of subjects to experimental and control groups with a pre-test and post-test for both groups.
What is a cohort?A group of people who all experience a significant event in roughly the same time frame.


What is a control group?A group of subjects who do not receive the experimental treatment or test stimulus.
What are demand characteristics?Aspects of the research situation that cause participants to guess the purpose or rationale of the study and adjust their behavior or opinions accordingly.
What is a deviant case study?Study of a case that deviates from other cases and from what prevailing theory would lead the researcher to expect.
What is an experimental design?framework that ensures that the test and control groups of an experiment are identical in every way except for the independent variable


What is an experimental effect?Effect, usually measured numerically, of the independent variable on the dependent variable.
What is a experimental group?A group of subjects who receive the experimental treatment or test stimulus.
What is experimental mortality?A differential loss of subjects from experimental and control groups that affects the equivalency of groups; threat to internal validity.
What is experimentation?A research design in which the researcher controls exposure to the test factor or independent variable, the assignment of subjects to groups, and the measurement of responses.


Define external validity.The ability to generalize from one set of research findings to other situations.
What are extraneous factors?Factors besides the independent variable that may cause change in the dependent variable.
What is a factorial design?Experimental design used to measure the effect of two or more independent variables singly and in combination.
What is a field experiment?Experimental designs applied in a natural setting.


What is a formal model?A simplified and abstract representation of reality that can be expressed verbally, mathematically, or in some other symbolic system, and that purports to show how variables or parts of a system are interconnected.
What are history effects?A change in the dependent variable due to changes in the environment over time; threat to internal validity.
What is instrument Decay?A change in the measurement device used to measure the dependent variable, producing change in measurements; threat to internal validity.
What is instrument reactivity?Reaction of subjects to a pre-test.


What is internal validity?The ability to show that manipulation or variation of the independent variable actually causes the dependent variable to change.
What is an intervention analysis?Also known as interrupted time series design. A non-experimental design in which the impact of a naturally occurring event (intervention) on a dependent variable is measured over time.
What is a laboratory experiment?In a laboratory experiment, the control group and the test group are studied in an environment created wholly by the investigator.
What is maturation effect?A change in subjects over time that affects the dependent variable; threat to internal validity.


What is a multi-group Design?Experimental design with more than one control and experimental group.
What is a non-experimental design?A research design characterized by at least one of the following: presence of a single group, lack of researcher control over the assignment of subjects to control and experimental groups, lack of researcher control over application of the independent variable, or inability of the researcher to measure the dependent variable before and after exposure to the independent variable occurs.
What are observational studies?In social science research, many studies observe the outcomes for available subjects on variables without any experimental manipulation of the subjects.
What is Panel Mortality?Loss of participants from a panel study.


What is a Period Effect?An indicator or measure of history effects on a dependent variable during a specified time period.
What is a post-test?Measurement of the dependent variable after manipulation of the independent variable.
What is precision matching?matching of pairs of subjects with one of the pair assigned to the experimental group and the other to the control group.
What is a pretreatment measurement?Measurement of the dependent variable prior to the administration of the experimental treatment or manipulation of the independent variable.


What is random assignment?The random assignment of subjects to the experimental and control groups.
What is a repeated measurement design?An experimental design in which the dependent variable is measured at multiple times after the treatment is administered.
What is a research design?A plan specifying how the researcher intends to fulfill the goals of the study; a logical plan for testing hypotheses.
What is a rival explanation?a cause for variation the dependent variable that is an alternative to the hypothesized explanation


Define selection bias.Bias in the assignment of subjects to the experimental and control groups; threat to internal validity.
What is a simple post-test design?Weak type of experimental design with control and experimental groups but no pre-test.
What is a simulation?A simple representation of a system by a device in order to study its behavior.
What is a small-N design?Type of experimental design in which one ro a few cases of a phenomenon are examined in considerable detail, typically using several data collection methods, such as personal interviews, document analysis, and observation.


What is statistical regression?Change in the dependent variable due to the temporary nature of extreme values; threat to internal validity.
What is survey research?The direct or indirect solicitation of information from individuals by asking them questions, having them fill out forms, or using other means.
What is a test group?a group of subjects receiving treatment
What is a test stimulus (test factor)?The independent variable introduced and controlled by an investigator in order to assess its effects on a response or dependent variable.


What are testing effects?Effect of a pre-test on the dependent variable; threat to internal validity.
What is a time series design?A research design featuring multiple measurements of the dependent variable before and after experimental treatment.
What is informed consent?procedures that inform potential research subjects about the proposed research in which they are being asked to participate. The principle that researchers must obtain the freely given consent of human subjects before they participate in a research project
What is an institutional review board (IRB)?panel to which researchers must submit descriptions of proposed research involving human subjects for the purpose of ethics review


What is human subject research?Research that involves manipulating the behavior of human subjects for general research purposes.
What is a cluster sample?Used when the population of interest is hard to randomly sample but occupies a definite geography. May involve organizing population into clusters, then randomly sampling clusters.
What is a convenience sample?Researcher studies cases that are most easily at hand; for example, university researchers commonly use convenience samples of undergraduate students.
What is double-blind peer review?Review process before publication of research that involves researchers reviewing articles without knowing the author(s) and the author(s) do not know who the reviewers are.


What is the fundamental problem of causal inference?A causal effect is the difference between two outcomes, but we only observe one outcome. To study causal relationships, we must make assumptions about the unobserved outcome.
What is the likely voter model?Model for public opinions that involves removing data from those unlike to vote when the poll is related to voter behavior. It is easier to get a broad sample that includes non-voters, who are later excluded, rather than get a sample of only likely voters.
What is a most different systems design?Design that uses cases that are different in many respects except for sharing similar values of the dependent variable to rule out their dissimilarities as potential explanations for variation in the dependent variable.
What is a most similar systems design?Design that involves using cases that are similar but have differing levels of the dependent variable in order to develop and evaluated possible explanations for variation in the dependent variable.


What is p-hacking?Practice that involves purposefully manipulating statistical analysis to achieve statistically significant results.
What is post hoc theorizing?Practice of changing the hypothesis and underlying theory after collecting data in order to “predict” results that are in line with the already-collected data.
What is post-treatment measurement?Process of measuring the dependent variable after completing treatment or invention. Necessary in experimental research.
What is a purposive sample?Sample selection that involves choosing cases that offer the best test of the research hypothesis. Also called judgmental sample.


What is a random sample?A sample randomly drawn from the population. Every member of population has equal chance of selection. Typically hard to achieve.
What is random selection?Occurs when every member of the population has an equal chance of being included in the sample.
What is response bias?Occurs when some cases in the sample are more likely than others to be measured.
What is a sampling frame?The population the researcher wants to analyze and the source from which samples are drawn.


What are sampling weights?May be done when researchers know how their sample observations compare to population dimensions. Overrepresented groups are given weaker weights while groups underrepresented in the sample are given greater weights.
What is a simple random sample?Each individual has chance to be selected and each participant is selected at random.
What is a snowball sample?Participants are asked to identify others who may be able to participate in research. A non-random sample method.
What is a stratified random sample?Involves dividing the population into groups. The researcher then takes a random sample within each strata. This method can assure than all subpopulations are represented in a sample.


What is a systematic sample?Sampling method involving the selection of elements from an ordered sample frame, such as sampling every 20th individual listed in a directory.