Controls help an experimenter regulate and validate an experiment. They let the experimenter factor out trends (such as a rising temperature or increasing light intensity) that could influence what is observed during the experiment. This is essential to check that an experiment has appropriate randomization.
Subject(s) used for comparison who are not given a treatment under study or who do not have a given condition, background, or risk factor that is the object of study. Control conditions may be concurrent (occurring more or less simultaneously with the condition under study) or historical (preceding the condition under study). When the present condition of participants is compared with their own condition on a prior regimen or treatment, the study is considered historically controlled.
The group in a clinical study who are receiving treatment other than that being investigated. Controls may receive no treatment, a placebo, or a commonly used treatment for that condition that acts as a marker of effectiveness.
Controls are those participants in a study who did not receive the experimental drug, test or intervention.
(experimental) A group that comprises those who do not have the disease, intervention, procedure or whatever is being studied, but in all other respects is as nearly identical to the test group as possible. The control group is compared to the test group to help identify the effects of the disease, intervention, procedure, etc.
According to the classification algorithm, identifies whether the study used control animals from the same population as the affected animals (Yes or No). For example, many studies compare control animals from an "uncontaminated" reference site to animals from a "contaminated" site. In this case, the control field would indicate "no", controls not drawn from the same population.
Statistical and evaluation design procedures to isolate the effect of one factor on some outcome from that of others. A group of people or areas not getting a response that are compared to those receiving the response to show what would have happened to the response group if the response group had not received the intervention (see Control group) 47, 48, 49, 51
In a case-control study, controls are those people, places, times, or events that do not have the outcome being studied, in contrast to cases which do have the outcome. For example, in a case-control study of high-assault bars, the cases are bars with many assaults and the controls are bars with few or no assaults (see Cases, and Case-control study) 32, 33
Experimental controls are the steps taken to identify and deal with (in advance of the study) any potential confounding variable.
a technique used to evaluate experimental treatments by having two groups of experimental subjects, on to receive treatment, and one subjected to the same conditions but not given the treatment. This way, scientists can find out whether effects they are seeing are due to treatment or some other experimental condition. Non-controlled experiments are considered very difficult to evaluate because of the absence of controls with which to compare treated subjects.
A group of people or animals that does not receive a treatment or other intervention or that is not affected with the disease being studied. This group is used as a standard to compare any changes in a group that receives treatment or has the disease. In Alzheimer research patients are often compared with controls of the same age (age-matched) to rule out the effects of age on study results.