How to Use the Internet to Find & Understand Clinical Trials

Clinical trials are an important part of the medical research process. They answer questions which help researchers determine how well a particular medical approach works.

Answers to the following questions can help you understand what a clinical trial is and help you determine how and if you should participate in one.

1. What is a Clinical Trial?

A clinical trial is a health-related study in which researchers investigate medical approaches to determine how well they work in people. They can also help researchers determine if new therapies or treatments are safe and if they are better than current practices. The studies can be designed to be either interventional or observational. Interventional studies are those in which the trial participants are assigned by the investigator to a treatment or other intervention, and their outcomes are measured. Observational studies are those in which participants are observed, surveyed or watched, and their outcomes or answers are analyzed by the investigators. Clinical trials come in different phases. To minimize human risk, the trials usually start small, with Phase I trials, and get larger as the safety is determined. In Phase I and II trials, the results are used to determine the safety, side effects, etc. In Phase III and IV trials, the experimental intervention is given to larger groups of people to determine its effectiveness, side effects, and to compare it to other treatments.

2. How are Clinical Trials designed?

Clinical trials come in many shapes and sizes. Clinical trials are funded and designed by various groups or organizations such as medical institutions, foundations, pharmaceutical companies, and federal agencies. Many trials have at least two groups, also called arms; one group of participants is given the intervention while the other group, the control, is given a standard treatment or a placebo. A placebo is an inactive intervention, like a sugar pill, that is given to some study participants to enable a comparison between the placebo and the actual intervention. Most of the time you are assigned to a group randomly to make sure that the results are because of the intervention and not due to other factors. Most clinical trials will randomize (like a coin toss) you to one of the groups. That means that you may or may not be in the group receiving the intervention.

3. Why should I participate in one?

You may want to consider participating in a clinical trial for a variety of reasons. You may have the opportunity to gain access to new research treatments before they are widely available, or to treatments you may not have been able to afford. Clinical trials are a very important part of the medical research and discovery process. You can help in this process and possibly help researchers save, improve, or extend human life. You should be aware that you could be part of the control group and thus would not receive the actual treatment. However, this is important for research as the control group can then be compared to the group that receives the treatment or intervention.

4. Who can participate in a clinical trial?

All clinical trials have predetermined guidelines about who can or cannot participate. These guidelines are known as the inclusion/exclusion criteria and are an important principle of medical research that helps to produce reliable results. Inclusion criteria are those factors that allow someone to participate in the trial. Conversely, the exclusion criteria defines those who are not allowed to participate in the trial. While each trial is different, these factors usually include characteristics such as age, gender, the type and stage of a disease, previous treatment history, and other medical conditions. Remember the inclusion and exclusion criteria are formed before the trial begins accepting participants. Being rejected from a clinical trial is not a personal rejection. Researchers want to make sure that the criteria ensure the study is looking at similar participants, will ensure the safety of each participant, and will help them answer the question the clinical trial seeks to answer.

5. How can I find out more about clinical trials in the area? is a registry of federally and privately supported clinical trials conducted in the United States and around the world. This registry will provide you with information on a trial such as the purpose, who may participate, the location(s), and a contact person. Other places that may have additional trials or information on a trial are the National Cancer Institute and the NIH Clinical Center. Check with your local health providers, universities, or hospitals for other opportunities.

6. What are the risks and benefits?

It is very important that you carefully consider the risks and benefits of any clinical trial you are considering. Participating in a clinical trial allows you to take an active role in your health care and receive medical care before it is readily available or affordable. Due to the experimental nature of clinical trials there can be serious risks. These risks vary by trial and could include an unpleasant or even life-threatening side effect or ineffective treatments. You will also need to be aware of the amount of time a trial may take (travel, doctor visits, lab work, etc).

7. How is the safety of participants protected?

The ethical and legal codes that govern medical practice also apply to clinical trials. In addition, most clinical research is federally regulated with safeguards to protect the participants. Trials follow a carefully controlled protocol, or study plan, which details what researchers will do in the study. As a clinical trial progresses, researchers report the results of the trial at scientific meetings, to medical journals, and to various government agencies. Individual participants’ names will remain secret and will not be mentioned in these reports. Make sure you are honest with the researchers and answer all of their questions fully so they can ensure your safety and the quality of the information they gather.

8. What should I consider before participating in a trial?

You should fully understand the purpose of the clinical trial you are considering as well as your rights as a participant, your roles or duties in the trial (such as the drug regime you will have to follow, doctor visits, etc), any costs you may need to cover (travel expenses or time off work), how long the trial lasts, how you will be assigned to a group, the care you can expect, and the risks and benefits, and any other alternative treatments you should consider first. You will be given an informed consent document that will give you detailed information on the clinical trial. You should discuss all of this information with your family and your doctor. While you must sign the document to be enrolled in the clinical trial, remember this is not a contract and you may withdraw at any time.

9. Can I leave a trial?

Yes! You are a voluntary participant and may leave a clinical trial at any time for any reason. Talk to the trial doctors to make sure it is safe to discontinue a drug (some drugs may need to be tapered off) and talk to your own doctor to determine if you need to resume or begin therapy in place of the study therapy. You should also let the research team know and give them your reasons for leaving the study. Researchers try to collect all needed data from each participant in order to make sure they have the data needed to make valid conclusions from the study. While it is acceptable to leave a study, it is important you realize that this affects the quality of the data the researchers have to make conclusions.

10. Need more information?

MedlinePlus has an interactive tutorial as well as basic information and links to more information on their Clinical Trials health topic page. You may also be interested in their Understanding Medical Research health topic.


Page authored by Terri Ottosen
Health Sciences Library at UNC-Chapel Hill.

Last updated October 2, 2018 at 4:34 pm