Randomized controlled trial
The randomized controlled trial (RCT English: randomized controlled trial ) is in medical research demonstrated the best study design to obtain a clear statement in a unique question and to prove causality. Therefore, the study design or the research design is also spoken by the "gold standard". In addition, RCTs are used, among other things, in the psychological and economic research.
The Evidence-based medicine emphasizes the importance of RCTs as the best basis to meet empirical evidence of the effectiveness of treatments to patient-oriented decisions.
RCTs are a type of experiment ( " a methodically -scale investigation into the empirical extraction of information (data )").
Definition of Terms
Randomization
Randomization means that the assignment to a treatment group ( approximately drug A or B ) is carried out at random. The purpose of randomization is
Form and implementation of randomization must be mentioned in the study.
Controlled study
Controls ie the study because the results with those of the control group ( the group with a reference value ) are compared with no intervention or a control intervention in the study group. The control intervention is either the most potent measure or a sham intervention (with medications: placebo).
The study group is also testing, intervention or treatment group (Latin verum, " the truth " as opposed to placebo, the true form of treatment, such as drug-containing drug) called. The control group is also used as settlement or placebo group (if placebos are used ) refers.
An extension is the so -called crossover design dar. Here the intervention and control group are changed to the study center.
Example
In a poor Indian region in which had hitherto been hardly vaccinated, built by the Indian state to a vaccination system. In every village there was a Impfschwester. Nevertheless, only a few percent of the parents brought their child ( after the fifth vaccination of vaccination was complete) five times to vaccinate. With an RCT, researchers examined the effectiveness of measures against this vaccine fatigue. At the same time they used it to test the hypotheses why the poor their babies could not be vaccinated:
- Maybe they did not understand the benefits. Children who are vaccinated against measles, can still contract malaria or get diarrhea.
- Perhaps parents kept the vaccination ineffective.
- Maybe a superstition was to blame: children could catch the evil eye (that's why babies are hardly taken up to the first birthday with out ).
- Against such beliefs any vaccination program is powerless, many believed helper.
At random, the researchers divided 134 villages in three groups:
- In 74 villages, everything remained the same.
- In 30 villages once an infirmary was built in the month in which a nurse free the children vaccinated.
- In the 30 other villages there was not only the monthly Impfcamp, but the parents also received two pounds of lenses when they brought their children for vaccination. At the end of the fifth vaccination you also gave parents two plates.
After one and a half years, the researchers took stock: In the villages with lenses and plates as a lure 38 percent of all children had received five vaccinations. In the villages with regular vaccination appointments 17 percent of all children were vaccinated by, in the remaining 74 villages, there were only 6 percent.
This proved: Superstition ( as he then was at parents ) obviously was not strong enough, the lure of a few pounds to resist lenses.
RCTs can therefore
- Investigate how efficient measures or
- Compare the efficiency of several alternative measures.
For example, an institution is faced with the choice to subsidize with money either staple ( a measure of all buyers benefit ) or pregnant women, young mothers and children to give food and vitamins for free. RCTs show that the latter is significantly more efficient measure: the benefits per euro spent is much higher.