Jacobson Center for Clinical & Translational Research

Research Study Participants

Choosing to participate in a clinical research study is an important personal decision. It is often helpful to talk to a physician, family members, or friends about deciding to join a study. After identifying study options, the next step is to contact the study research staff and ask questions about specific studies.

So, what is a clinical research study? Although there are many definitions of clinical research studies, they are generally considered to be biomedical or health-related research studies in human beings that follow a pre-defined protocol.

Current Research Studies

Frequently Asked Questions

Choosing to participate in a clinical research study is an important personal decision. The following questions provide detailed information about participating in clinical research studies. In addition, it is often helpful to talk to a physician, family members, or friends about deciding to join a study.

Why participate in a clinical research study? Participants in clinical research studies can play a more active role in their own health care, gain access to new research treatments before they are widely available, and help others by contributing to medical research.

Who can participate in a clinical research study? All clinical research studies have guidelines about who can participate. Using inclusion/exclusion criteria is an important principle of medical research that helps to produce reliable results. The factors that allow someone to participate in a clinical research study are called "inclusion criteria" and that exclude someone from participating are called "exclusion criteria". These criteria are based on such factors as age, gender, the type and stage of a disease, previous treatment history, and other medical conditions.

Before joining a clinical research study, a participant must qualify for the study. Some research studies seek participants with illnesses or conditions to be studied in the clinical research study, while others need healthy participants. It is important to note that inclusion and exclusion criteria are not used to reject people personally. Instead, the criteria are used to identify appropriate participants and keep them safe. The criteria help ensure that researchers will be able to answer the questions they plan to study.

What are the benefits and risks of participating in a clinical research study? 

Benefits Clinical research studies that are well-designed and well-executed are the best approach for eligible participants to:

  • Play an active role in their own health care.
  • Gain access to new research treatments before they are widely available.
  • Obtain expert medical care at leading health care facilities during the trial.
  • Help others by contributing to medical research

Risks There are risks to clinical research studies. There may be unpleasant, serious or even life-threatening side effects to an experimental treatment. The experimental treatment may not be effective for the participant. The protocol may require more of their time and attention than would a non-protocol treatment, including trips to the study site, more treatments, hospital stays or complex dosage requirements.

What are side effects and adverse reactions? Side effects are any undesired actions or effects of the experimental drug or treatment. Negative or adverse effects may include headache, nausea, hair loss, skin irritation, or other physical problems. Experimental treatments must be evaluated for both immediate and long-term side effects.

How is the safety of the participant protected? The ethical and legal codes that govern medical practice also apply to clinical research studies. In addition, most clinical research is federally regulated with built in safeguards to protect the participants. The trial follows a carefully controlled protocol, a study plan which details what researchers will do in the study. As a clinical research study 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.

What kind of preparation should a potential participant make for the meeting with the research coordinator or doctor?

  • Plan ahead and write down possible questions to ask.
  • Ask a friend or relative to come along for support and to hear the responses to the questions.

Every clinical research study in the U.S. must be approved and monitored by an Institutional Review Board (IRB) to make sure the risks are as low as possible and are worth any potential benefits. An IRB is an independent committee of physicians, statisticians, community advocates, and others that ensures that a clinical research study is ethical and the rights of study participants are protected. All institutions that conduct or support biomedical research involving people must, by federal regulation, have an IRB that initially approves and periodically reviews the research.

Does a participant continue to work with a primary health care provider while in a clinical research study? Yes. Most clinical research studies provide short-term treatments related to a designated illness or condition, but do not provide extended or complete primary health care. In addition, by having the health care provider work with the research team, the participant can ensure that other medications or treatments will not conflict with the protocol.

Can a participant leave a clinical research study after it has begun? Yes. A participant can leave a clinical research study at any time. When withdrawing from the study, the participant should let the research team know about it, and the reasons for leaving the study. Leaving a study will not affect your current or future health care with the institution. 

Who sponsors clinical research studies? Clinical research studies are sponsored or funded by a variety of organizations or individuals such as physicians, medical institutions, foundations, voluntary groups, and pharmaceutical companies, in addition to federal agencies such as the National Institutes of Health (NIH), the Department of Defense (DOD), and the Department of Veteran's Affairs (VA). Trials can take place in a variety of locations, such as hospitals, universities, doctors' offices, or community clinics.

Information is copyright  U.S. National Library of Medicine.

Questions to ask before participating in a clinical research study

What should people consider before participating in a clinical research study?

People should know as much as possible about the clinical research study and feel comfortable asking the members of the health care team questions about it, the care expected while in a study, and the cost of the study. The following questions might be helpful for the participant to discuss with the health care team.

  • What is the purpose of the study?
  • Who is going to be in the study?
  • How many volunteers are needed for the study?
  • Why do researchers believe the experimental treatment being tested may be effective? Has it been tested before?
  • Have there been other studies similar to this one?
  • What kinds of tests and experimental treatments are involved?
  • How do the possible risks, side effects, and benefits in the study compare with my current treatment?
  • How might this study affect my daily life?
  • How long will the study last?
  • Will hospitalization be required?
  • What are the standard treatment options for my condition if I choose not to participate?
  • Who will pay for the experimental treatment?
  • Will I incur any costs?
  • Will I be reimbursed for other expenses or paid for my participation?
  • What type of long-term follow up care is part of this study?
  • How will I know that the experimental treatment is working? Will results of the study be provided to me?
  • Who will be in charge of my care?
  • Whom should I contact if I have questions about the study?

Information is copyright  U.S. National Library of Medicine.

Glossary of Study Terms

The following glossary was prepared to help the consumer become familiar with many of the common terms used in clinical research studies. 

Adverse Reaction An unwanted effect caused by the administration of drugs. Onset may be sudden or develop over time.

 Advocacy and Support Groups Organizations and groups that actively support participants and their families with valuable resources, including self-empowerment and survival tools. 

Approved Drugs In the U.S., the Food and Drug Administration (FDA) must approve a substance as a drug before it can be marketed. The approval process involves several steps including pre-clinical laboratory and animal studies, clinical trials for safety and efficacy, filing of a New Drug Application by the manufacturer of the drug, FDA review of the application, and FDA approval/rejection of application. 

Assent A minor's agreement to participate in a clinical research study. 

Arms Any of the treatment groups in a randomized study. Most randomized studies have two "arms," but some have three "arms," or even more. 

Baseline 1. Information gathered at the beginning of a study from which variations found in the study are measured. 2. A known value or quantity with which an unknown is compared when measured or assessed. 3. The initial time point in a clinical trial, just before a participant starts to receive the experimental treatment which is being tested. At this reference point, measurable values such as CD4 count are recorded. Safety and efficacy of a drug are often determined by monitoring changes from the baseline values. 

Bias When a point of view prevents impartial judgment on issues relating to the subject of that point of view. In clinical studies, bias is controlled by blinding and randomization. 

Blind A randomized clinical research study is "Blind" if the participant is not told which arm of the trial he is on. A clinical research study is "Blind" if participants are unaware on whether they are in the experimental or control arm of the study; also called masked. 

Clinical Pertaining to or founded on observation and treatment of participants, as distinguished from theoretical or basic science. 

Clinical Investigator A medical researcher in charge of carrying out a clinical trial's protocol.

Clinical Research Coordinator A person who helps the investigator run a clinical study.  Also called a “Study Coordinator” or “Nurse Coordinator”. 

Clinical Research Study A clinical research study is a research study to answer specific questions about vaccines or new therapies or new ways of using known treatments. Clinical research studies are used to determine whether new drugs or treatments are both safe and effective. Carefully conducted clinical trials are the fastest and safest way to find treatments that work in people. Trials are in four phases: Phase I tests a new drug or treatment in a small group; Phase II expands the study to a larger group of people; Phase III expands the study to an even larger group of people; and Phase IV takes place after the drug or treatment has been licensed and marketed. 

Cohort In epidemiology, a group of individuals with some characteristics in common. 

Community Based Clinical Research Study (CBCT) A clinical research study conducted primarily through primary-care physicians rather than academic research facilities. 

Compassionate Use A method of providing experimental therapeutics prior to final FDA approval for use in humans. This procedure is used with very sick individuals who have no other treatment options. Often, case-by-case approval must be obtained from the FDA for "compassionate use" of a drug or therapy. 

Complementary and Alternative Therapy Broad range of healing philosophies, approaches, and therapies that Western (conventional) medicine does not commonly use to promote well-being or treat health conditions. Examples include acupuncture, herbs, etc. 

Confidentiality Regarding Clinical Research Study Participants Refers to maintaining the confidentiality of trial participants including their personal identity and all personal medical information. The trial participants' consent to the use of records for data verification purposes should be obtained prior to the trial and assurance must be given that confidentiality will be maintained. 

Contraindication A specific circumstance when the use of certain treatments could be harmful. 

Control A control is the nature of the intervention control. 

Control Group The standard by which experimental observations are evaluated. In many clinical research studies, one group of patients will be given an experimental drug or treatment, while the control group is given either a standard treatment for the illness or a placebo. 

Controlled Clinical Research Studies Control is a standard against which experimental observations may be evaluated. In clinical research studies, one group of participants is given an experimental drug, while another group (i.e., the control group) is given either a standard treatment for the disease or a placebo. 

Data Safety and Monitoring Board (DSMB) An independent committee, composed of community representatives and clinical research experts, that reviews data while a clinical trial is in progress to ensure that participants are not exposed to undue risk. A DSMB may recommend that a trial be stopped if there are safety concerns or if the trial objectives have been achieved. 

Diagnostic Clinical Research Studies Refers to research studies that are are conducted to find better tests or procedures for diagnosing a particular disease or condition. Diagnostic studies usually include people who have signs or symptoms of the disease or condition being studied. 

Dose-Ranging Study A clinical research study in which two or more doses of an agent (such as a drug) are tested against each other to determine which dose works best and is least harmful. 

Double-Blind Study A clinical research study design in which neither the participating individuals nor the study staff knows which participants are receiving the experimental drug and which are receiving a placebo (or another therapy). Double-blind trials are thought to produce objective results, since the expectations of the doctor and the participant about the experimental drug do not affect the outcome; also called double-masked study. 

Drug-Drug Interaction A modification of the effect of a drug when administered with another drug. The effect may be an increase or a decrease in the action of either substance, or it may be an adverse effect that is not normally associated with either drug. 

Efficacy (Of a drug or treatment). The maximum ability of a drug or treatment to produce a result regardless of dosage. A drug passes efficacy trials if it is effective at the dose tested and against the illness for which it is prescribed. In the procedure mandated by the FDA, Phase II clinical trials gauge efficacy, and Phase III trials confirm it. 

Eligibility Criteria Summary criteria for participant selection; includes Inclusion and Exclusion criteria.

Empirical Based on experimental data, not on a theory. 

EndPoint Overall outcome that the protocol is designed to evaluate. Common endpoints are severe toxicity, disease progression, or death. 

Enrolling The act of signing up participants into a study. Generally this process involves evaluating a participant with respect to the eligibility criteria of the study and going through the informed consent process.  

Epidemiology The branch of medical science that deals with the study of incidence and distribution and control of a disease in a population. 

Expanded Access Refers to any of the FDA procedures, such as compassionate use, parallel track, and treatment IND that distribute experimental drugs to participants who are failing on currently available treatments for their condition and also are unable to participate in ongoing clinical research studies. 

Experimental Drug A drug that is not FDA licensed for use in humans, or as a treatment for a particular condition. 

Food and Drug Administration (FDA) The U.S. Department of Health and Human Services agency responsible for ensuring the safety and effectiveness of all drugs, biologics, vaccines, and medical devices, including those used in the diagnosis, treatment, and prevention of HIV infection, AIDS, and AIDS-related opportunistic infections. The FDA also works with the blood banking industry to safeguard the nation's blood supply. 

Hypothesis A supposition or assumption advanced as a basis for reasoning or argument, or as a guide to experimental investigation. 

Inclusion/Exclusion Criteria The medical or social standards determining whether a person may or may not be allowed to enter a clinical research study. These criteria are based on such factors as age, gender, the type and stage of a disease, previous treatment history, and other medical conditions. It is important to note that inclusion and exclusion criteria are not used to reject people personally, but rather to identify appropriate participants and keep them safe. 

Informed Consent The process of learning the key facts about a clinical research study before deciding whether or not to participate. It is also a continuing process throughout the study to provide information for participants. To help someone decide whether or not to participate, the doctors and nurses involved in the trial explain the details of the study. 

Informed Consent Document A document that describes the rights of the study participants, and includes details about the study, such as its purpose, duration, required procedures, and key contacts. Risks and potential benefits are explained in the informed consent document. The participant then decides whether or not to sign the document. Informed consent is not a contract, and the participant may withdraw from the clinical research study at any time. 

Institutional Review Board (IRB)1. A committee of physicians, statisticians, researchers, community advocates, and others that ensures that a clinical research study is ethical and that the rights of study participants are protected. All clinical trials in the U.S. must be approved by an IRB before they begin. 2. Every institution that conducts or supports biomedical or behavioral research involving human participants must, by federal regulation, have an IRB that initially approves and periodically reviews the research in order to protect the rights of human participants. 

Intent To Treat Analysis of a clinical research study results that includes all data from participants in the groups to which they were randomized even if they never received the treatment. 

Intervention Name The generic name of the precise intervention being studied. 

Interventions Primary interventions being studied: types of interventions are Drug, Gene Transfer, Vaccine, Behavior, Device, or Procedure. 

Investigational New Drug A new drug, antibiotic drug, or biological drug that is used in a clinical investigation. It also includes a biological product used in vitro for diagnostic purposes. 

Masked The knowledge of intervention assignment. 

Natural History Study Study of the natural development of something (such as an organism or a disease) over a period of time. 

New Drug Application (NDA) An application submitted by the manufacturer of a drug to the FDA - after clinical research studies have been completed - for a license to market the drug for a specified indication. 

Off-Label Use A drug prescribed for conditions other than those approved by the FDA.  

Open-Label Clinical Research Study A clinical research study in which doctors and participants know which drug or vaccine is being administered. 

Orphan Drugs An FDA category that refers to medications used to treat diseases and conditions that occur rarely. There is little financial incentive for the pharmaceutical industry to develop medications for these diseases or conditions. Orphan drug status, however, gives a manufacturer specific financial incentives to develop and provide such medications.

Participant One who participates in a clinical research study

Peer Review Review of a clinical research study by experts chosen by the study sponsor. These experts review the studies for scientific merit, participant safety, and ethical considerations. 

Pharmacokinetics The processes (in a living organism) of absorption, distribution, metabolism, and excretion of a drug or vaccine. 

Phase I Trials Initial studies to determine the metabolism and pharmacologic actions of drugs in humans, the side effects associated with increasing doses, and to gain early evidence of effectiveness; may include healthy participants and/or patients. 

Phase II Trials Controlled clinical studies conducted to evaluate the effectiveness of the drug for a particular indication or indications in patients with the disease or condition under study and to determine the common short-term side effects and risks.  

Phase III Trials Expanded controlled and uncontrolled trials after preliminary evidence suggesting effectiveness of the drug has been obtained, and are intended to gather additional information to evaluate the overall benefit-risk relationship of the drug and provide and adequate basis for physician labeling.  

Phase IV Trials Post-marketing studies to delineate additional information including the drug's risks, benefits, and optimal use.  

Placebo A placebo is an inactive pill, liquid, or powder that has no treatment value. In clinical trials, experimental treatments are often compared with placebos to assess the treatment's effectiveness. 

Placebo Controlled Study A method of investigation of drugs in which an inactive substance (the placebo) is given to one group of participants, while the drug being tested is given to another group. The results obtained in the two groups are then compared to see if the investigational treatment is more effective in treating the condition. 

Placebo Effect A physical or emotional change, occurring after a substance is taken or administered, that is not the result of any special property of the substance. The change may be beneficial, reflecting the expectations of the participant and, often, the expectations of the person giving the substance. 

Preclinical Refers to the testing of experimental drugs in the test tube or in animals - the testing that occurs before trials in humans may be carried out. 

Prevention Clinical Research Studies Refers to trials to find better ways to prevent disease in people who have never had the disease or to prevent a disease from returning. These approaches may include medicines, vaccines, vitamins, minerals, or lifestyle changes. 

Protocol A study plan on which all clinical research studies are based. The plan is carefully designed to safeguard the health of the participants as well as answer specific research questions. A protocol describes what types of people may participate in the trial; the schedule of tests, procedures, medications, and dosages; and the length of the study. While in a clinical trial, participants following a protocol are seen regularly by the research staff to monitor their health and to determine the safety and effectiveness of their treatment. 

Quality of Life Clinical Research Studies Refers to studies that explore ways to improve comfort and quality of life for individuals with a chronic illness. 

Randomization A method based on chance by which study participants are assigned to a treatment group. Randomization minimizes the differences among groups by equally distributing people with particular characteristics among all the trial arms. The researchers do not know which treatment is better. From what is known at the time, any one of the treatments chosen could be of benefit to the participant. 

Randomized Clinical Research Study A study in which participants are randomly (by chance) assigned to one of two or more treatment arms of a clinical research study. Occasionally placebos are utilized. 

Recruiting The period during which a study is attempting to identify and enroll participants. Recruitment activities can include advertising and other ways of soliciting interest from possible participants. 

Recruitment Status Indicates the current stage of a study, whether it is planned, ongoing, or completed. Possible values include:

  • Not yet recruiting: participants are not yet being recruited or enrolled
  • Recruiting: participants are currently being recruited and enrolled
  • Enrolling by invitation: participants are being (or will be) selected from a predetermined population
  • Active, not recruiting: study is ongoing (i.e., patients are being treated or examined), but enrollment has completed
  • Completed: the study has concluded normally; participants are no longer being examined or treated (i.e., last patient's last visit has occurred)
  • Suspended: recruiting or enrolling participants has halted prematurely but potentially will resume
  • Terminated: recruiting or enrolling participants has halted prematurely and will not resume; participants are no longer being examined or treated
  • Withdrawn: study halted prematurely, prior to enrollment of first participant

Risk-Benefit Ratio The risk to individual participants versus the potential benefits. The risk/benefit ratio may differ depending on the condition being treated. 

Screening Clinical Research Studies Refers to studies which test the best way to detect certain diseases or health conditions. 

Side Effects Any undesired actions or effects of a drug or treatment. Negative or adverse effects may include headache, nausea, hair loss, skin irritation, or other physical problems. Experimental drugs must be evaluated for both immediate and long-term side effects. 

Single-Blind Study A study in which one party, either the investigator or participant, is unaware of what medication the participant is taking; also called single-masked study. 

Standard Treatment A treatment currently in wide use and approved by the FDA, considered to be effective in the treatment of a specific disease or condition.  

Standards of Care Treatment regimen or medical management based on state of the art participant care. 

Statistical Significance The probability that an event or difference occurred by chance alone. In clinical trials, the level of statistical significance depends on the number of participants studied and the observations made, as well as the magnitude of differences observed. 

Study Endpoint A primary or secondary outcome used to judge the effectiveness of a treatment. 

Study Type The primary investigative techniques used in an observational protocol; types are Purpose, Duration, Selection, and Timing. 

Toxicity An adverse effect produced by a drug that is detrimental to the participant's health. The level of toxicity associated with a drug will vary depending on the condition which the drug is used to treat. 

Treatment IND IND stands for Investigational New Drug application, which is part of the process to get approval from the FDA for marketing a new prescription drug in the U.S. It makes promising new drugs available to desperately ill participants as early in the drug development process as possible. Treatment INDs are made available to participants before general marketing begins, typically during Phase III studies. To be considered for a treatment IND a participant cannot be eligible to be in the definitive clinical trial. 

Treatment Clinical Research Study Refers to studies which test new treatments, new combinations of drugs, or new approaches to surgery or radiation therapy.

Information is copyright  U.S. National Library of Medicine.

Additional Information about Clinical Research Studies

Last Updated: 6/27/22