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NREPP Glossary

The following definitions have been drawn from numerous sources and are tailored specifically for content on the NREPP Web site. The terms defined here may have slightly different meanings in other settings.

Co-occurring disorders

In the context of NREPP, substance abuse and mental disorders that often occur in the same individual at the same time (e.g., alcohol dependence and depression); also known as comorbid disorders.

Comparative effectiveness research

Comparison group

A group of individuals that serves as the basis for comparison when assessing the effects of an intervention on a treatment group. A comparison group typically receives some treatment other than they would normally receive and is therefore distinguished from a control group, which often receives no treatment or "usual" treatment. To make the comparison valid, the composition and characteristics of the comparison group should resemble that of the treatment group as closely as possible. Some studies use a control group in addition to a comparison group.

Confidence interval

In scientific studies, a range that conveys the precision of a measurement. Sometimes abbreviated as CI, a confidence interval is a range of values above and below the average measurement for a sample. For example, the average measurement of a depression score for a sample of people might be reported as 75 ± 5. The confidence interval therefore ranges from 70 to 80. This value allows researchers to have confidence that the actual average measurement of a depression score for all possible people is from 70 to 80, even though the average measurement for the sample is 75. Although a variety of confidence intervals can be calculated, the 95% confidence interval is most commonly used. A 95% confidence interval indicates that researchers could repeat the sampling procedure many times, and the calculated confidence interval would include the true average measurement for all possible people 95% of the time.

Confounding variables

In an experiment, any characteristic that differs between the experimental group and the comparison group and is not the independent variable under study. These characteristics or variables "confound" the ability to explain the experimental results because they provide an alternative explanation for any observed differences in outcome. In assessing a classroom curriculum, for example, a confounding variable would exist if some students were taught by a highly experienced instructor while other students were taught by a less experienced instructor. The difference in the instructors' experience level makes it harder to determine if the differences in student outcomes (e.g., grades) were caused by the effects of the curriculum or by the variation in instructors. The likelihood that confounding variables might have affected the outcomes of a study is one of the six NREPP criteria used to rate Quality of Research.

Control group

A group of individuals that serves as the basis of comparison when assessing the effects of an intervention on a treatment group. Depending upon the study design, a control group may receive no treatment, a "usual" or "standard" treatment, or a placebo. The composition and characteristics of the control group should resemble that of the treatment group as closely as possible to make the comparison valid.

Core components

The most essential and indispensable components of an intervention (core intervention components) or the most essential and indispensable components of an implementation program (core implementation components).

Cultural appropriateness

In the context of public health, sensitivity to the differences among ethnic, racial, and/or linguistic groups and awareness of how people's cultural background, beliefs, traditions, socioeconomic status, history, and other factors affect their needs and how they respond to services. Generally used to describe interventions or practices.

Cultural competence

In the context of public health, the knowledge and sensitivity necessary to tailor interventions and services to reflect the norms and culture of the target population and avoid styles of behavior and communication that are inappropriate, marginalizing, or offensive to that population. Generally used to describe people or institutions. Because of the changing nature of people and cultures, cultural competence is seen as a continual and evolving process of adaptation and refinement.