Clinical trial design may be of many forms and sizes. These are divided into the following categories:
In terms of whether or not a control group was available to serve as a baseline for the experimental treatment:
- unrestricted examinations
- controlled tests
Depending on how participants were allocated to a treatment or control group, we will have the following outcomes:
- Unrandomized trials
- Experiments that are conducted at random
Depending on whether participants or researchers are aware of the therapy group to which they have been allocated, we will have the following information:
- Research under an open label
- Blind investigation
Given the significance of the projected differences between the treatment and control groups:
- competitions for dominance
- Bioequivalence trials
- Non-inferiority trials
Regarding the treatment plan:
- concurrent proceedings
- crossover research
- consecutive examinations
Depending on whether or not a control group was present:
Uncontrolled Trials: A patient group without a control group is used in this kind of research to compare the efficacy or toxicity of a drug. The results may be compared to those of comparable studies or to those of other researchers. Uncontrolled Phase I and II studies that look at a new drug’s pharmacokinetic features or tolerated dose intervals are common.
Closely watched trials include: The study group is compared to a control group that might receive a placebo or another effective medication in these studies. The two groups are examined simultaneously. This kind of experiment accounts for the vast majority of phase III studies.
Depending on the method of participant allocation:
Clinical Trials Without Randomization: The investigator is in responsibility of allocating participants to the different treatment groups, arms, or controls in these research.
Randomized Controlled clinical trials include: Participants in these studies are randomised at random to treatment groups, treatment arms, or controls. Randomization is the process of randomly allocating people to either treatment arms or control groups. To achieve this, many methods such as closed envelopes, computer-generated sequences, random numbers, and so on may be used. Randomization prevents participants from decoding the sequence and determining which group they were assigned to, as well as researchers from arbitrarily allocating patients to different groups.
Depending on whether participants or researchers knew about the assigned group:
Open-Label Studies: Research studies in which the researchers know which patients will be assigned to which groups. Researchers may accidentally impact the outcomes of these studies by employing subjective criteria depending on their knowledge of the patient’s medical treatment.
Bias in clinical trials may arise when trial participants and/or investigators are aware of who is receiving treatment (or a placebo). This prejudice might be intentional or inadvertent.
Single-Blind Study: In this case, volunteers are uninformed of their group assignment, while researchers are.
No one knows about the patient’s therapy since neither the research team nor the volunteers know which group the patient was assigned to.
Given the significance of the expected difference in performance across groups:
Parallel Trials: Each patient group receives just one course of treatment in this design. Cross-over Trials: Over a period of time, each patient receives each of the trial treatments in turn. Cross-over designs may raise ethical concerns when a patient who was responding well to one treatment is switched to the other.
Patients are matched for successive trials, with one in the experimental group and one in the control group. Results are examined as they arrive and integrated with previous data. The sample size (the number of patients included) is determined by the overall results rather than being predetermined.