Evidence Based

Built on scientifice findings, especially practice and policies founded upon the results of randomized, controlled experiments.

Evidence-Based Criminology

A form of contempory criminology that makes use of rigorous social scientific techniques, especially randomized, controlled experiments and the systematic review of research results; also called knowledge-based criminology.


A tenative explanation accounting for a set of facts that can be tested by further investigation.


A series of interrelated propositions that attempts to describe, explain, predict, and ultimately control some class of events. A theory gains explanatory power from inherent logical consistency and is “tested” by how well it describes and predicts reality.


The use of standardized, systematic procedures in the search for knowledge.

Applied Research

Research based on scientific inquiry that is designed and carried out with practical applications in mind.

Pure Research

Research undertaken simply for the sake of advancing scientific knowledge.

Primary Research

Research characterized by original and direct investigation.

Secondary Research

Research based on new evaluations of existing information that has been collected by other researches.


A concept that can undergo measurable changes.


The process by which concepts are made measurable.

Research Design

The logic and structure inherent in an approach to data gathering.

Confounding Effect

A rival explanation or competing hypothesis that is a threat to the internal or external validity of a research design.

Internal Validity

The certainty that experimental interventions did indeed cause the changes observed in the study group.

External Validity

The ability to generalize research findings to other settings.

Controlled Experiment

An experiment that attempts to hold conditions (other than the intentionally introduced experimental intervention) constant.

Quasi-Experimental Design

An approach to research that, although less powerful than experimental designs , is deemed worthy of use when
better designs are not feasible.

Control Group

A group of experimental subjects that, although the subject of measurement and obserbations, is not exposed to the expermental intervention.


The process whereby individuals are assigned to study groups without biases or differences resulting from selection.

Survey Research

Research using a social science data-gathering technique that involves the use of questionaires.

Participant Observation

A strategy in data gathering in which the researcher observes a group by participation, to varying degrees, in the activities of the group.


A scientifc principle that requires that independent observers see the same thing under the same circumstances for observations to be regarded as valid.