An experiment in which subjects are randomly assigned to “treatment†and “control†groups, so ensuring that potentially confounding variables will be uniform across both groups (thereby preventing confounding from distorting the association between treatment and outcome).
Trial where people are put into groups by chance. One group is given the best current treatment or a placebo and their progress is compared with those having the treatment that is being tested. People are usually selected for each group by a computer.
A study in which people are assigned by chance (e.g. flip of a coin) to receive either an experimental treatment or no treatment (e.g. placebo or usual care). People in the study are the same at onset and are cared for in exactly the same way throughout the trial. Any differences between the two groups at the end of the trial can then be attributed to the difference in treatment alone, and not to bias or chance.
A type of research or experiment used to compare the effectiveness of different treatments. Patients are randomly assigned to groups.The groups either receive the treatment being assessed or are a control group. The control group receive dummy (placebo) medication. RCTs offer the most reliable form of evidence for effectiveness.
A study in which subjects are allocated at random to different interventions and/or intervention and control groups. The intention is to eliminate the possibility that any impacts arose due to differences between the subjects in these groups rather than the intervention. Such studies are rare and may suffer from low external validity (Drug and Alcohol Findings 2000).
In a randomised trial participants are assigned by chance to receive either an experimental or control treatment. The idea behind the randomised trial is that when it is done properly, the effect of a treatment can be studied in groups of people who are the same at the outset, and treated in the same way, except for the intervention being studied. Any differences then seen in the groups at the end of the trial can be attributed to the difference in treatment alone, and not to bias or chance.
An RCT is the accepted way to judge the efficacy of a drug. A drug is allocated randomly to half the trial volunteers, while the other half receive a different treatment or a placebo. By comparing the responses of the two groups, researchers can see just how much difference the treatment under trial makes. Many RCTs are also 'double-blinded' meaning that neither volunteer nor researcher knows who is getting the real treatment.
Randomised controlled trials have at least two groups of participants and treatments are assigned to eligible patients at random. The randomisation process is usually done by a computer. One group will receive the treatment being tested and another group will receive their usual treatment or the existing standard; the latter is called the control group. A placebo or inactive preparation that appears identical to the test preparation may be given; in this way both the patient and investigator can be unaware at the time ('double-blind') which the patient was receiving. This reduces potential for bias in the collection or analysis of results.
A prospective research trial in which a group of individuals is randomised (ie allocated at random) into one or more experimental groups or study groups and a control group. The control group may receive a placebo or an existing treatment and the treatment group(s) will receive the treatment(s) or intervention(s) under investigation. All the groups are followed up for the variables/outcomes of interest.
an essential tool of medical research. An RCT is a study in which people are allocated (randomised) to different treatments and the effects of those treatments are compared. Some of these people may be randomised to a placebo or a standard treatment (the control), so that the effects of the test medication can be more clearly observed.
An experimental comparison study in which participants are allocated to treatment / intervention or control / placebo groups using a random mechanism, such as coin toss, random number table, or computer-generated random numbers. Participants have an equal chance of being allocated to an intervention or control group and therefore allocation bias is eliminated. Randomisation relies on large subject numbers to be successful as bias can occur by chance clustering of characteristics even in RCTs. Any RCT shold therefore analyse subject groups for potential differences. Trials in which people in a population are randomly allocated into two groups, usually called study and control groups, to receive or not to receive an intervention. For trials to assess screening procedures, the study group is offered screening and the control group is not. The results are assessed by comparing rates of death (or other end points) from the disease in the two groups. RCTs are generally regarded as the most scientifically rigorous method of assessing the efficacy of screening.
Is a trial in which subjects are randomly assigned to two (or more) groups: one (the experimental group) receiving the intervention that is being tested, and the other (the comparison group or controls) receiving an alternative treatment. The groups are then followed up to see if any differences between them result.