Glossary

applied research Applied research seeks knowledge that will modify or improve the present situation.

archival  Source of evidence based on records or documents relating the activities of individuals, institutions, governments, and other groups; used as an alternative to or in conjunction with other research methods.

baseline The first stage of a single-case experiment, in which a record is made of an individual's behavior prior to any intervention.

basic research Basic research mainly seeks knowledge about nature simply for the sake of understanding it better and to test theories.

causal inference  Identification of the cause or causes of a phenomenon.

confederate  Someone in the service of a researcher who is instructed to behave in a certain way in order to help produce an experimental treatment.

confidence intervals Intervals that indicate the range of values in which we can expect a population value to fall with a specified degree of confidence (e.g., .95).

control  Key component of the scientific method whereby the effect of various factors possibly responsible for a phenomenon are isolated.

convenience sample A sample of research participants that is selected because individuals are available and willing to participate in the research project.

correlational research  Research in which the goal is to identify predictive relationships among naturally occurring variables.

debriefing  The process following a research session through which participants are informed about the rationale for the research in which they participated, about the need for any deception, and about their specific contribution to the research. Important goals of debriefing are to clear up any misconceptions and to leave participants with a positive feeling toward psychological research.

deception  Intentionally withholding information about significant aspects of a research project from a participant or presenting misinformation about the research to participants.

dependent variable A measure of behavior used by a researcher to assess the effect (if any) of the independent variables.

descriptive statistics Numerical measures of sample characteristics, such as the mean (average score) and standard deviation (degree of dispersal around the mean).

effect size An index of the strength of the relationship between the independent variable and dependent variable.

empirical approach  Approach to acquiring knowledge that emphasizes direct observation and experimentation as a way of answering questions.

experimental research design  A research study in which a treatment (intervention) is implemented with a high degree of control, permitting an appropriate comparison (e.g., between treatment and control groups) such that an unambiguous decision can be made concerning the effect of the treatment.

external validity  The extent to which the results of a research study can be generalized to different populations, settings, and conditions.

holding conditions constant A method for conducting a controlled experiment in which only the independent variable is allowed to vary; all other potential factors are the same for participants in different conditions of the experiment.

hypothesis  A tentative explanation for a phenomenon.

independent variable A factor the researcher manipulates with at least two levels in order to determine the effect on behavior.

inferential statistics Statistical procedure for testing whether the differences in a dependent variable that are associated with various conditions of an experiment are reliable-that is, larger than would be expected on the basis of chance alone.

informed consent  The explicitly expressed willingness to participate in a research project, based on clear understanding of the nature of the research, of the consequences of not participating, and of all factors that might be expected to influence willingness to participate.

Institutional Animal Care and Use Committee (IACUC) A committee that evaluates the risks and benefits of research proposals involving animal subjects.

Institutional Review Board (IRB) A committee that evaluates the risks and benefits of proposals involving research with human participants.

internal validity The degree to which differences in performance can be attributed unambiguously to an effect of an independent variable, as opposed to an effect of some other (uncontrolled) variable.

mean The average score in a distribution of scores; calculated by adding all of the scores and dividing by the number of scores.

minimal risk  A research participant is said to experience minimal risk when probability and magnitude of harm or discomfort anticipated in the research are not greater than that ordinarily encountered in daily life or during the performance of routine tests.

null hypothesis testing A statistical procedure in which, as the first step in statistical inference, the independent variable is assumed to have had no effect.

observational research Observation of naturally occurring behavior, with the goal of describing behavior.

operational definition  A procedure whereby a concept is defined solely in terms of the operations used to produce and measure it.

quasi-experiments  Procedures that resemble the characteristics of true experiments, for example, an intervention or a treatment is used and a comparison is provided, but procedures lack the degree of control found in true experiments.

random assignment The most common technique for forming groups as part of an independent groups design; the goal is to establish equivalent groups by balancing individual differences in the participants across the conditions of the experiment.

random sample A sample in which every member of the population has an equal chance of being selected for the research project.

reliability  A measurement is reliable when it is consistent.

replication  Repeating the exact procedures used in an experiment to determine whether the same results are obtained.

risk/benefit ratio  The subjective evaluation of the risk of the proposed research relative to the benefit, both to the individual and to society.

scientific method  Approach to knowledge that emphasizes empirical rather than intuitive processes, testable hypotheses, systematic and controlled observation of operationally defined phenomena, data collection using accurate and precise instrumentation, valid and reliable measures, and objective reporting of results; scientists tend to be critical and, most importantly, skeptical.

standard deviation A measure of variability or dispersion that indicates how far, on average, a score is from the mean.

statistically significant  When the probability of an obtained difference in an experiment is smaller than would be expected if chance alone were assumed to be responsible for the difference, the difference is statistically significant.

theory  A logically organized set of propositions that defines events, describes relationships among events, and explains the occurrence of these events; scientific theories guide research and organize empirical knowledge.

validity  The "truthfulness" of a measure; a valid measure is one that measures what it claims to measure.

variable A condition (factor) that can vary, either quantitatively or qualitatively, along an observable dimension. Researchers both measure and control variables.