Some clinical studies can suffer from bias issues, leading to results that are not as reliable as they need to be to provide answers to scientific or medical questions. To help avoid the pitfalls of bias, scientists turn to randomized clinical studies.
In the United States, randomized clinical studies comprise 65% of all clinical trials. But what is a randomized clinical study, and how does it work?
A randomized clinical study is one in which participants are randomly assigned to the control or experimental group. It ensures neither the patients nor the people conducting the study know what group the participants are in. The outcome variable is the only expected difference between the control and experimental group.
Randomized clinical studies are seen as the highest level of evidence in clinical practice because of the reliability of the results, helping illuminate the scientific understanding of effects, especially when there’s uncertainty around those effects.
The randomization method needs to be determined at the planning stage of the randomized clinical study. The main methods of randomization include:
Simple randomization is the process of using only one sequence of random assignments. The most commonly used ways of achieving single randomization are by turning to a deck of cards, a coin toss, or a random number table.
Although simple randomization is a good choice for a clinical study involving a large population, it is less so for smaller groupings.
Another method of randomization is block randomization. This is when participants are randomized into groups that contain equal sample sizes. Block randomization ensures a balanced sample size throughout the clinical study.
The stratified randomization method focuses on balancing and controlling the influence of the participants’ baseline characteristics, called covariates. The researcher must identify the specific covariates, taking into account how each of those covariates can affect the results.
By building a separate group to address each covariate and performing randomization within those groups, you can get more accurate results.
Covariate adaptive randomization is a good choice for small to medium randomized clinical studies. This is because a small clinical study that only relies on simple randomization can end up with imbalances in covariates among the treatment group.
In covariate adaptive randomization, a participant is sequentially assigned to a group while the investigator takes into account the previous assignments of other participants as well as the specific covariates that person has.
Allocation concealment is an important factor for successful randomization. It means that none of the people involved in the recruitment process can predict the next testing group.
This method helps prevent the problem of investigators assigning specific patients to certain groups, which could end with an imbalance or exaggeration of the results.
A randomized clinical study ensures patients’ characteristics are distributed evenly so that differences in the outcome of the trial come down to the treatment the patient received. Randomized clinical studies offer the investigation of cause-effect relationships while removing bias and other factors.
Another benefit a randomized clinical study offers is the chance to determine whether a particular treatment is better than the traditional treatment or a placebo. It can also determine whether the treatment is no worse than the standard treatment or placebo.
These kinds of tests are easier to blind than observational studies while at the same time helping clearly identify the populations of all of the participants because of the thorough preregistration information participants have to provide. It’s also easier to analyze the results of randomized clinical studies by using statistical tools.
Identifying the appropriate research facility and methodologies are critical in ensuring the credibility and accuracy of study outcomes. For most investigators, the preference for a randomized clinical study is rooted in its ability to deliver reliable results.
At Orlando Clinical Research Center, we specialize in running phase I-IV clinical trials for biotech or pharmaceutical companies, helping evaluate the efficacy and safety of drugs or treatments. Our custom built 35,000 sq. ft. research site specifically designed for Phase 1 trials.