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Explaining Clinical Research and Clinical Trials


What is clinical research?

Clinical research is the step in the translational research pathway where humans first get involved. All experiments involving humans are called either “clinical trials” or “clinical studies”.  This clinical research process is an improvement over the old days, when researchers depended on accidental discoveries. Nowadays, they thoroughly plan and carefully conduct research. At the same time, medical treatment has progressed from the simple relief of symptoms to understanding how diseases do what they do. In some cases, research can lead to the actual curing of diseases.

What is clinical trials?

Clinical trials are prospective biomedical or behavioral research studies of human subjects that are designed to answer specific questions about biomedical or behavioral interventions (drugs, treatments, devices, or new ways of using known drugs, treatments, or devices). Clinical trials are used to determine whether new biomedical or behavioral interventions are safe, efficacious, and effective.

Biomedical clinical trials of an experimental drug, treatment, device, or behavioral intervention may proceed through four phases:

  • Phase I. Tests a new biomedical intervention in a small group of people (e.g. 20-80) for the first time to determine efficacy and evaluate safety (e.g., determine a safe dosage range and identify side effects).
  • Phase II. Study the biomedical or behavioral intervention in a larger group of people (several hundred) to determine efficacy and further evaluate safety.
  • Phase III. Study to determine efficacy of the biomedical or behavioral intervention in large groups of people (from several hundred to several thousand) by comparing the intervention to other standard or experimental interventions as well as to monitor adverse effects, and to collect information that will allow the interventions to be used safely.
  • Phase IV. Studies conducted after the intervention has been marketed. These studies are designed to monitor the effectiveness of the approved intervention in the general population and to collect information about any adverse effects associated with widespread use.

How is research made safe?

There are many safeguards in place to help keep research safe, including eligibility criteria and review by an Institutional Review Board (IRB). Watch the video to learn more:

How is research made safe (2.5 min)

If research involves a drug, device, or procedure, the FDA must first approve the research before testing can be done in humans.

If a drug is found to work in humans (i.e., it is “effective”) without serious side effects (i.e., it is “safe”), it still has to go through more approval by the FDA before it finally becomes available for doctors and patients to use.

Who is involved in clinical research?

It takes many people for success!

  • The SPONSOR of the clinical trial provides the primary funding and may also have a role in its design and conduct. Often, the sponsor is a federal agency such as the National Institutes of Health (NIH) or a pharmaceutical company.
  • A key person in the research study is the PRINCIPAL INVESTIGATOR, commonly called the "PI." The PI conducts the clinical research, and may have designed it or may have been chosen to conduct it by a sponsor.
  • At each research institution is a group of persons known as the INSTITUTIONAL REVIEW BOARD (IRB). The IRB consists of doctors, scientists, and non-medical persons from the community, who must review and approve all clinical research done at that institution. No clinical research can be started without IRB approval.
  • The most important person of all in every clinical trial is the volunteer PARTICIPANT, sometimes called the research subject. Without these volunteers no clinical research can be done!

How are studies designed?

Clinical research studies are designed to be informative and safe. The following videos explain some of the common elements, including who can participate, control groups and randomization, seen in research studies.

What is a control group? (2 min)

What is random assignment? (3 min)

Who can participate in research? (2 min)

Who can become a participant in clinical research?

All clinical trials have guidelines that explain who can participate. The guidelines are based on factors such as age, medical history, illness, and current medication. These factors are used to identify appropriate people to participate, and keep them safe.

Clinical trials also often need people who are free from disease or illness to serve as "healthy subjects" or CONTROLS—people who are compared to the research participants who actually have the disease or illness that is being studied.

For ways to volunteer for a research study, please click here.

What is informed consent? It has two parts:

A clinical researcher or his/her colleague explains the study to you, and answers all your questions. This is the “informed” part.

If all of the conditions that they explain to you are acceptable to you, and if you agree to participate in the study, then you sign the informed consent form. This is the “consent” part.

What should I do before joining a clinical trial?

Be sure that you have answers to the following questions before giving consent:

  • Who is the Principal Investigator? or Who is the sponsor?
  • Are there any personal benefits from this trial?
  • What are the risks?
  • What tests and procedures will be performed as part of this study?
  • Will I be paid for participating in this clinical trial? How much?
  • What medications or foods do I have to avoid? What activities do I have to avoid?
  • What medications or foods do I have to take? What activities do I have to perform?
  • What alternative treatments are available outside of this clinical trial?

Also, make sure that:

  • The language in the informed consent document is clear to you
  • You can ask any questions you want
  • The consent form that you read and sign was approved by the IRB. There should be a dated stamp on the document certifying that it was approved by the IRB
  • The consent form says that you can leave the trial at any time you wish. You will be able to get medical care even if you leave the clinical trial
  • The consent form says that the PI can discontinue you from the trial at any time
  • The consent form says that you keep all your legal rights even if you sign the consent
  • You are given a copy of the informed consent document to keep, and a copy of the Research Subject's Bill of Rights

Why do people get involved and decide to participate?

There are many reasons that people decide to get involved in research. Watch the following videos to see a few stories.

NIH Clinical Research Trials and You - Personal Stories

Seniors Making a Difference” (10 min) English

“¿Por qué debemos participar en studios de investigación?" (10 min) (Español)
(“Why should we participate in Research Studies?”) (10 min) Spanish

How can I learn more?

You can view easy-to-understand videos about clinical research on our Educational Videos section below. Plus you can look up unfamiliar words in our Clinical Research Glossary found below as well. You can always send an email to and we may be able to help.

What is Translational Research?

What is translational research?

Translational research is research aimed at translating results in basic research into results that directly benefit humans. Scientists have ideas about something they would like to test out, and they seek resources for experiments. Most experiments start in the laboratory and this is called “basic research”. Many new treatments are tested in animals before any humans are permitted to try them out. And even then, many types of experiments need to be done before a new medical device or treatment is approved for regular use by your doctor and other clinicians. The phrase “translational research” is all the steps in this process.

Even after a new medical treatment is available for use, translational research is not always complete because researchers try to get feedback from patients and their doctors and try to make the treatment even better. Promoting the new treatment to patients, health insurance companies, public health departments, and doctors is often also part of “translational research".

Translational research involves moving knowledge and discovery gained from the basic sciences to its application in clinical and community settings. This concept is often summarized by the phrases "bench-to-bedside" and "bedside-to-community" research.

For translational research to be successful, communication must be bi-directional. In other words, many different people have to talk—and listen—to each other: basic researchers and clinical researchers; clinical researchers and human volunteers; patients and their doctors in their communities; and community doctors and clinical researchers.

What does the ACTRI have to do with translational research?

The ACTRI is part of a national Clinical and Translational Science Award (CTSA) consortium created to accelerate laboratory discoveries into treatments for patients by facilitating research resources for all investigators. The CTSA program is led by the National Institutes of Health's National Center for Advancing Translational Sciences (NCATS).

The main goal of the ACTRI is to make our research discoveries more rapid, effective, and useful to the general public. We improve health care by providing scientists and community leaders with resources and information, and we encourage interactions between all those different people mentioned above. We also offer many educational programs for scientists, students, and the public. Those are some of the ways we try to help speed up the translation of great ideas into great therapies.

In order to evaluate and improve our efforts to advance translational research, the ACTRI has adapted and embraced the multi-T phase concept of translational research, described below.

Example of T0-T4 Translational Health Research

Research Phase Definition Type of Research Examples


Identification of opportunities and approaches to health problem.

Basic research question Are there specific gene mutations associated with breast cancer?


Discovery of candidate health application Phase I and II clinical trials; observational studies Is there an association between BRCA mutations and breast cancer?


Health application to evidence-based practice guidelines Phase III clinical trials; observational studies; evidence synthesis and guidelines development What is the positive predictive value of BRCA mutations in at-risk women?


Practice guidelines to health practices Dissemination research; implementation research; diffusion research Phase IV clinical trials What proportion of women who meet the family history criteria are tested for BRCA and what are the barriers to testing?


Practice to population health impact Outcomes research (includes many disciplines); population monitoring of morbidity, mortality, benefits, and risks studies

Does BRCA testing in asymptomatic women reduce breast cancer incidence or improve outcomes?

Glossary of Clinical Research Terms

Adverse event: any unexpected change in health or any side effect that occurs in a person while they are still under the effect of a treatment in a clinical trial.  All adverse events must be reported to an institutional review board, whether they are serious or minor.

Assent: a child’s consent to participate in a clinical trial.

Blinded study: a study done in such a way that the study participants do not know whether they are getting a placebo (an inactive substance) or a drug, but the study team does know.  If the study is comparing two different doses or two different medications, then the human participants do not know which they are getting.  In a “double-blinded study”, neither the study participant nor the investigator know which treatment any one study participant is getting. That information is revealed only once the treatment is over.

Clinical investigation or ‘clinical research’ or ‘clinical study’ or ‘clinical trial’: research that either directly involves human participants or uses materials of human origin (for example, blood) to test the safety and/or effectiveness of drugs, medical devices, procedures, or preventions.

Confidentiality: the assurance that a participant’s information will be kept secret and that access to that information is limited to authorized persons.

Control group: the group of participants who resemble the experimental group, (for example, they are in the same age range) but who do not receive the experimental treatment.  Changes are measured in both the treatment group and this group, to compare the effect of the new drug, medical device, procedure, or prevention.

Data: series of recorded observations, measurements, or facts (about the participant).

Effectiveness/efficacy: whether a new drug or treatment works. An effective drug or prevention will improve health or successfully prevent a disease.

Experimental drug or device:  see Investigational drug or device.

Experimental group: the group of subjects exposed to the new, researched treatment.  This group is often compared to a ‘control group’, the subjects who are are not exposed to that treatment.

FDA (Food and Drug Administration): an agency of the United States federal government that approves or disapproves new drugs and devices.

Human subject: a participant who volunteers to be in a clinical study.

Informed consent: a patient’s written consent to participate in a clinical study after fully discussing with the researchers all the relevant health-related facts and the risks involved.

Institutional Review Board, “IRB”: a committee that has been formally designated to protect the people involved in research.  This board must review and approve each clinical study that involves humans subjects, with the aim to protect each person’s safety, rights, privacy and welfare.

Investigation: see Clinical investigation

Investigational drug/device: a new medical drug and/or device that has been tested in a laboratory but has not yet been approved by the Food and Drug Administration (FDA) to be legally sold and used by health care providers and/or patients.

Investigators: These are researchers.  They are scientists who manage clinical studies. The lead investigator of a study is also called the “Principal Investigator.”

Participant: also known as a "human subject", a person who volunteers to be in a research experiment.

Placebo: a substance that has no therapeutic effect but is given merely to satisfy a patient who supposes it could be a medicine. Other names for placebos include ‘dummy pill’ or ‘sugar pill’.

Procedure:  In health care, this can be a test (such as taking blood to measure cholesterol) or a treatment (like surgery or an injection of a drug). In research, a trial's protocol describes the procedures (tests and/or treatments) carried out on or by the participants and/or investigators.

Protected health information (PHI): any information about a participant’s health history or status. By law, this is required to be kept confidential.

Protocol: a written plan for carrying out a clinical study. A protocol includes what will be done, when, and how.

Randomization: Mixing up the types of participants in enrolled into an experimental group or a control group, so that it will be fair to compare the two groups. For example, if the experimental group had a lot more elderly people than the control group, and the test drug didn't work in the experimental group, it wouldn't be fair to conclude that the drug didn't work, because there might be something in elderly people's metabolism to prevent the drug from working well. So a mix of people should go into the group that gets the drug, and a mix of people should go into the control group.

Randomized controlled trial (RCT):  a scientific experiment that tests a new treatment or device by randomly dividing participants to receive either the treatment under investigation, or a control condition that does not receive the investigated treatment.

Research: gathering of information to help increase our knowledge. Clinical research involves human volunteers. Sometimes clinical research tests drugs or devices or procedures in human participants; but research always involves measuring something--for example, whether blood pressure went down in participants receiving a new drug, and whether it stayed the same in the participants (controls) who didn't receive the drug.

Researcher: a person who carries out an investigation (another word that can be used for “investigator”).

Sponsor: a person, organization, company, institution, or government agency that provides funds (money) or other resources for a clinical study.

Study: see Clinical investigation

Study Coordinator: a key member of the research team who works for the principal investigator, or lead researcher. He/she is the person who is usually responsible for the daily activities of the clinical study.

Subject:  subject or ‘human subject’ is a term describing the person who volunteers to be in a research experiment.  Also called a research participant.

Trial: see ‘clinical investigation’

Volunteer: a person who willingly participates in a clinical study.

Clinical Trial Activation Roadmaps

ACTRI has developed a new roadmap tool to guide Principal Investigators and study team members through the process of activating clinical trials and/ or research studies at UCSD.

This comprehensive tool provides a step-by step approach to this complex process and has the advantage of offering additional resources such as links, notes, request forms, and documents to guide our users in a one-stop-shop.

Whether used as standard operating procedure or for training purposes, this resource is part of the vision of the ACTRI to facilitate research for faculty and study teams at UCSD.

Industry-sponsored Clinical Trial Activation Roadmap

To explore the map above and learn about each individual step:

PI-Initiated Clinical Trial Activation Roadmap


For information or questions about the Roadmap or help with navigating research at UCSD, contact


Research Ethics

Research Ethics for ACTRI Education, Training and Career Development




The UC San Diego Research Ethics Program offers a variety of courses, workshops, and seminars. The topics covered are those associated with responsible conduct of research (RCR), which include, for example, conflict of interest, mentor/mentee responsibilities, data management and research subject protections (see: NIH RCR requirements). In addition, education may focus on more specialized topics including, for example, digital health (e.g., artificial intelligence, predictive analytics), gene editing and stem cell research. 


Scientific Ethics
Formal and informal training in research ethics is an important aspect of the professional development of scientists and engineers. The rules, cultures and disciplinary differences are sometimes obvious and other times nuanced and it is important to know how to navigate and discriminate between hard and fast rules and not so clear conventions. Research ethics education may also be a requirement of a funding agency. This 14-hour course is delivered over 7-sessions and may be used to satisfy a NIH or NSF training requirement; however, whether course completion is used for that purpose is determined by the advisor and/or department.
Ethics and Survival Skills [on hold]
Building Research Integrity and Capacity (BRIC)
Through a partnership with the UC San Diego Research Center for Optimal Digital Ethics in Health (ReCODE Health), researchers have access to instruction developed to increase research literacy among Community Health Workers/Promotores who assist with community and clinic-based research studies. The course is available on-line via: ReCODE Health, BRIC Course
Designing Research for Diversity
Through a partnership with the UC San Diego Research Center for Optimal Digital Ethics in Health (ReCODE Health) and ACTRI, researchers have access to instruction developed to increase awareness when planning to engage under-represented populations in research. This course is offered online and has been adapted for delivery through the CREST program. This course is available through CREST and online: ReCODE Health, Designing Research for Diversity Course
An Interactive Guide for Promotores de Salud/Community Health Workers 
This course is designed to increase research literacy and awareness of ethical research practices among community members involved in academic research. Our target learners are research team members, including Promotores and Community Health Workers, who assist with designing and implementing community and clinic-based health research. Learn more here.


Train-the-trainer workshops are available for faculty who are interested in learning ways to promote ethical and responsible research.
Reproducibility and Rigor
With support from the ACTRI, the Research Ethics Program offers a two-hour workshop module on reproducibility to promote reflection and discussion about fostering reproducible research.
Ethics in Artificial Intelligence and Digital Health
Increasingly, digital tools and strategies are used in biomedical and behavioral research. A 2-hour workshop is available to learn about how pervasive sensors, social media platforms and mobile devices are being used with a focus on the related ethical, legal and social implications associated with “digital health” research.
Ethical Challenges in Research
We offer monthly workshops through the Office of Postdoctoral Scholar Affairs on topics associated with research ethics. See the Office of Postdoctoral Scholar Affairs website.

Teaching/Learning Resources



The purpose of consultation is to clarify ethical challenges, possible courses of action, and strategies for mitigating future challenges. Consultations are a pathway to clarifying and resolving disputes, possible misunderstandings, or misconduct in the practice of research. Consultations might focus on regulated areas of research such as conflicts of interest and research subject protections as well as unregulated aspects of research such as collaborations, mentor/mentee relationships and our societal responsibilities.  
Public/Community Engagement
Identifying and confirming best practices with respect to ethical standards in research can benefit from engagement with the public. Research Ethics Program faculty are experienced in staging public forums to promote discussion of complex ethical issues. Unique challenges include, but are not limited to, designing research that will involve vulnerable populations and returning results to research participants. Ethics faculty also have a role in communicating with the public through interviews with journalists and publishing op-ed pieces. Opportunities for public engagement are further facilitated by the overlapping roles of the UC San Diego Research Ethics Program, the Institute for Practical Ethics and the San Diego Research Ethics Consortium.
Policy Development
Assistance is available to research groups, schools/departments, the ACTRI, and the University in the development of policies, guidelines, or procedures that support the responsible and ethical conduct of research. The assistance offered includes facilitation, writing, or providing models or suggestions.




Research is strengthened through the conduct of both normative analysis and empirical research designed to study and inform best practices. Our research has received extra and intramural support for over 20 years. Current research is carried out with support from the National Institutes of Health, National Science Foundation and Patient Centered Outcomes Research Institute. Areas of interest include: 1- creating/testing decision-making tools to support ethical AI/digital health research; 2- fostering ethical and responsible research environments, 3- informing participant communications including informed consent and return of results, and 4- developing ethically sourced health data repositories.

In addition to leading research programs, our faculty work with ACTRI researchers to support grant proposals. This may include addressing ethical issues proactively and/or developing aims to conduct research on ethical issues that are either central to or a part of clinical and translational research projects. In addition, ethics faculty contribute to required sections of grant proposals, particularly career development and fellowship awards, that require plans for research ethics education or addressing ethical challenges. 


Research Ethics Program