Clinical Research Glossary: Key Terms and Definitions

February 25, 2025

A

Additive Effect – The combined effect when two or more things are used together.

Adherence – Following the study directions and requirements.

Adverse Event – A negative change or medical occurrence that happens during a clinical trial or within a certain time period after the trial has ended. An adverse event may or may not be caused by the treatment being studied.

Adverse Reaction – A health problem that happens during the study and is reported as possibly caused by the study treatment.

Amendment – A change or update to a clinical trial protocol.

Analyze – To examine study data to answer a question and help reach conclusions.

Anonymize – Remove, change, or hide personal details to protect participant privacy.

Antibody – A protein made by the body to fight an illness or infection.

Antigen – A substance that causes the body’s immune system to react.

API – A set of programming instructions and standards for accessing a Web-based software application or Web tool. A software company releases its API to the public so that other software developers can design products powered by its service.

Arm – A group of participants in a research study who all receive the same study treatment.

Arm Assignment – The assignment of a group or subgroup of participants in a clinical trial to receive interventions, or no interventions, as specified in the study protocol.

Assessment – A procedure (e.g., a blood test, scan, etc.) used to generate data required by the trial.

Assent – Willingness to take part in a research study by someone who is not able to give legal consent.

Assent Form – A document used to explain the details of a research study to children or people who are unable to give legal consent.

Audit Trail – A record that logs all actions, including data entry and modifications, to ensure accountability and transparency in clinical trials.

B

Background therapy – Background therapy is the current medication that is routinely taken as a standard of care for a particular condition/disease.

Baseline assessment – Information that is collected and analyzed from a study participant at the start of a study.

Basket trial – A research study that tests one study treatment for different diseases and conditions.

Benefits of a research study – The ways a research study might help the participant and others.

Bias (research) – Flaws in the way a study is designed, done, or analyzed that lead to one conclusion being favored over another.

Biomarker – Something in the body that is measured as an indicator of personal health or disease.

Blinding – A type of clinical trial design in which one or more parties involved with the trial, such as the research team or participant, do not know which treatments have been assigned to which participants. See Double-blind and Single-blind below.

Blood draw – Taking a sample of blood by using a needle.

C

CDASH (Clinical Data Acquisition Standards Harmonization) – A standard way to collect data across studies and sponsors so that collection formats and structures provide clear traceability of submissions into the Study Data Tabulation Model (SDTM), delivering more transparency to regulators and others who conduct data review.

CDISC (Clinical Data Interchange Standards Consortium) – An organization that develops and advances data standards of the highest quality to transform incompatible formats, inconsistent methodologies, and diverse perspectives into a powerful framework for generating clinical research data.

CDP (Clinical Development Plan) – A document outlining the strategy for clinical trials, from initial phases to post-marketing studies.

CFR (Code of Federal Regulations) – A codification (arrangement of) the general and permanent rules published in the US Federal Register by the executive departments and agencies of the federal government. For eClinical systems, the most pertinent CFR section is 21 CFR 11.

CTD (Common Technical Document) – A standardized document format for submitting marketing authorization applications for pharmaceutical products.

Clinical benefit – A health change that researchers measure to show that the study treatment helps the study participants.

Clinical endpoint – A measurable outcome used to determine the effectiveness of a treatment.

Clinical research – A type of science that uses people’s data to study health, illness, behaviors, or conditions in careful and defined ways.

Clinical Research Coordinator (CRC) – A research staff member who helps manage studies.

Clinical study – A research study conducted in human volunteers to answer specific health questions. Interventional studies determine whether experimental treatments or new ways of using known therapies are safe and effective under controlled environments.

Clinical trial – A research study that tests drugs, devices, and treatments to see if they are safe and work in people.

Clinical Trial Registry – A public database where clinical trial information, such as trial design and progress, is registered and made available.

Clinician – A health care provider.

Cohort – A group of study participants that are similar in some way.

Collaborator – An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.

Comparative Effectiveness Research (CER) – A study comparing two or more treatments.

Comparator – Something that is compared to the study treatment.

Comparator Drug – A drug used in a clinical trial to compare against the investigational product.

Compensation (study) – Money and other forms of payment that may be given to participants for completing study activities.

Compliance – Following research requirements.

Computerized Tomography (CT) scan – A way to take pictures of the inside of a person’s body using a type of radiation and a computer.

Concomitant medications – Non-study medicines that are allowed to be taken at the same time as the study treatment.

Conduct – To do a study or procedure.

Confidence interval – The defined range of numbers used to describe where the results are expected to fall.

Confidentiality – Protecting personal information from people who should not have access.

Confounding – When the study outcome is influenced by outside conditions that were not expected by the study researchers.

Consent form – A document used to explain the planned research before a person decides whether or not to join a study.

Contract Research Organization (CRO) – A group that is paid by the study sponsor to support research studies.

Contraindicated – When things should not be used or done together because of possible harm.

Control – The control or “standard” treatment is compared against the investigational treatment. It is there to show that an approved treatment in the trial works, and the investigational treatment is compared against it.

Control group – The people in a study who do not receive the study treatment or do not have the condition being studied.

Correlation – When two or more measures are linked.

CRA (Clinical Research Associate) – A professional responsible for monitoring clinical trials to ensure compliance with regulatory guidelines, Good Clinical Practice (GCP), and the study protocol. CRAs work for sponsors, contract research organizations (CROs), or independent entities, overseeing trial sites, verifying data accuracy, and ensuring participant safety.

CRF (Case Report Form) – A standardized document used to collect clinical trial data.

Cross-over trial – A clinical trial where groups of volunteers are administered two or more interventions in a specific order. For example, a “two-by-two” cross-over trial design is where one group receives drug A at the beginning of the trial and then receives drug B for the rest of the trial. In the second group, participants receive drug B first and then drug A. Thus, the term “crossover” is used to describe the order in which they are assigned; for example, drug A and then drug B, or drug B and then drug A. All participants receive both drugs during the study.

CTA (Clinical Trial Agreement) – A legally binding contract between a sponsor, a clinical site, and/or investigators outlining the terms, responsibilities, financial agreements, and regulatory obligations for conducting a clinical trial.

CTA (Clinical Trial Assistant) – A professional supporting the clinical operations team by handling documentation, tracking study progress, coordinating trial logistics, and ensuring compliance with protocols and regulatory requirements.

CTM (Clinical Trial Manager) – A professional responsible for overseeing the planning, execution, and management of clinical trials. The Clinical Trial Manager ensures that trials are conducted according to regulatory guidelines, Good Clinical Practice (GCP), and study protocols. Their responsibilities include coordinating teams, managing budgets, ensuring compliance, and liaising with sponsors, investigators, and regulatory authorities.

CTMS (Clinical Trial Management System) – Defines and manages all the activities that span the lengthy and rigorous clinical trial process.

D

Data – Information collected from or about people taking part in a research study.

DMC/DSMB (Data Monitoring Committee/Data and Safety Monitoring Board) – An independent group of experts that reviews study data to make sure that patient safety is protected.

Database (research) – Information that has been collected and organized to be used for research.

Deviation – A departure from the trial protocol that occurs unintentionally.

DDE (Double Data Entry) – Performed when data is entered by two operators separately. The second pass entry (entry made by the second person) helps in verification and reconciliation by identifying the transcription errors and discrepancies caused by illegible data. DDE is used with paper-based case report forms.

DICOM (Digital Imaging and Communications in Medicine) – The international standard for transmitting, storing, retrieving, printing, processing, and displaying medical imaging information.

Dissent – Refusing to be part of a research study.

Discontinue (participant) – To remove a study participant from a study.

Discontinue (study treatment) – To stop a study treatment in a participant.

Disease progression – An illness getting worse over time.

Disease-free survival – The length of time after treatment that a person lives without the illness coming back.

Dose escalation study – A kind of study where increasing amounts of a study treatment are given to different groups to find the best dose.

Dosing discontinuation – Point/time when a patient volunteer permanently stops taking study drug for any reason. This may be at the end of the study or before the end if the patient wants to stop taking the medicine for some reason.

Double-blind – In a double-blind trial, only the study pharmacist knows what study medication a participant is receiving; the participants, doctors, nurses, and other clinical trial staff are not informed.

Double-blind study – A study that is set up so that the study treatment that each participant receives is not known by the participants or the researchers.

Drug Accountability – A system for tracking the use and storage of investigational products.

Drug holiday – A time period is decided between the participant and study team when a medication is stopped and then restarted.

Drug therapy – The use of medicine to treat a disease, condition, or symptom.

E

E-consent (form) – An electronic version of an informed consent form.

Efficacy – The ability of a treatment to produce the intended effect under controlled conditions.

eCRF (electronic case report form) – An electronic version of a case report form – an auditable electronic record of information generally reported to the sponsor on each trial subject, according to a clinical investigation protocol. The eCRF enables clinical investigation data to be systematically captured, reviewed, managed, stored, analyzed, and reported.

EDC (electronic data capture) – The computerized collection and management of clinical trial data from patients and subjects. An EDC system uses technology to streamline the collection and transmission of clinical trial data from the patient.

EHR (electronic health record) – A digital version of a patient’s paper chart. EHRs are real-time, patient-centered records that make information available instantly and securely to authorized users.

EMR (electronic medical record) – A digital version of a patient’s chart, typically used within a single healthcare provider’s organization for day-to-day operations.

Endpoint – A measure of the expected effect of the study treatment.

Enrol – The action of a participant joining the study after providing informed consent.

Enrolment – The point, or time, of a volunteer’s entry into the trial, after informed consent has been obtained. The same term may also be used to define the number of participants in a clinical trial.

ePRO – Electronic patient-reported outcomes (includes WebPRO – web-based patient-reported outcomes. Tools that use dedicated hand-held devices, mobile (phone/tablet) technology, or web portals to capture the status of a patient’s health condition that comes directly from the patient, without interpretation of the patient’s response by a clinician or anyone else.

eTMF (electronic trial master file) – An electronic collection of essential documents that allow the conduct of a clinical trial to be reconstructed and evaluated – basically the story of how the trial was conducted and managed.

Eligibility criteria – The requirements that people who want to participate in a clinical study must meet. Eligibility Criteria include both inclusion criteria and exclusion criteria and are defined in the protocol.

Effectiveness – How well a treatment works.

Efficacy – The ability of a treatment to produce the intended effect under controlled conditions.

Eligibility Criteria – The inclusion and exclusion factors determining who can participate in a trial.

EMA (European Medicines Agency) – European Medicines Agency. An agency of the European Union that oversees the use of medicinal products.

Epidemiologist – A person who studies where, why, how often, and to what populations health concerns and diseases happen.

Ethics Committee (EC) – A group that reviews clinical trials to protect participant rights and safety

ETL (extraction – transformation – loading) – A type of data integration that refers to the three steps (extract, transform, load) used to blend data from multiple sources. During this process, data is taken (extracted) from a source system, converted (transformed) into a format that can be analyzed, and stored (loaded) into a data warehouse or other system.

Equivalence – When two or more things in a study are about the same.

Equivalent (effect) – The same or almost the same result.

EudraCT (European Union Drug Regulatory Trials Database) – A database used by the European Medicines Agency to register clinical trials conducted in the EU.

Evaluate – To examine, review, and understand.

Exclusion criteria – A list of reasons a person cannot be included in a study.

Expanded access – A process for a doctor to request an unapproved treatment for a seriously ill patient.

Experimental – Something that is being tested in research but not yet proven.

Exploratory research – A process to find facts that can guide the design of future studies.

F

FDA (Food and Drug Administration) – Food and Drug Administration. A government agency within the U.S. Department of Health and Human Services that oversees the Nation’s public health by making sure that human and veterinary drugs, vaccines, biological products, medical devices, cosmetics, dietary supplements, the food supply, and any products that give off radiation are safe, effective, and secure.

Focus group – A group interview to learn what people think about a topic.

Frequency – How often something happens over a period of time.

GCP (Good Clinical Practice) – An international ethical and scientific quality standard for designing, conducting, recording, and reporting clinical trials. GCP ensures that:

• The rights, safety, and well-being of trial participants are protected.
• Clinical trial data is credible, accurate, and reliable.
• Trials comply with regulatory requirements and ethical guidelines.

GCP guidelines are established by the International Council for Harmonisation (ICH) and are followed globally to maintain consistency in clinical research.

Generalizability – How research results can apply to people who were not part of the study.

Genetic testing – A medical test that could identify a health risk to a person or their biological family members by looking at their genes (DNA).

GxP (Good Practice) – A collection of quality guidelines for various industries like GMP (Good Manufacturing Practice), GLP (Good Laboratory Practice), and GCP (Good Clinical Practice).

H

Health Authority – A national or international health agency that has authority over and regulates a clinical study.

Hazard ratio – A measure of risk that compares two treatments in the same study.

Healthy volunteer – A study participant who does not have a disease or condition, including the one being studied.

Hereditary – A parent’s features and traits being passed to their biological children before birth.

HIPAA (Health Insurance Portability and Accountability Act) – A U.S. law that provides data privacy and security provisions to safeguard medical information. HIPAA establishes national standards for the protection of health information

Human Subject – A participant in a clinical trial.

Hypothesis – An idea that is tested in a research study.

I

ICH (International Council for Harmonisation) – An organization that develops international guidelines for drug registration and clinical trials to ensure safety, efficacy, and quality.

Immune response – The body’s reaction to a substance, illness, or infection.

IMV (Interim Monitoring Visit) – A scheduled visit by a Clinical Research Associate (CRA) to a clinical trial site to ensure compliance with the protocol, Good Clinical Practice (GCP), and regulatory requirements. During an IMV, the CRA reviews source documents, verifies data, checks investigational product accountability, and ensures the site follows proper procedures.

IMVR (Interim Monitoring Visit Report) – A formal document summarizing findings from an IMV. It includes details on site performance, protocol adherence, identified issues, and any corrective actions needed.

IND (Investigational New Drug) – An application submitted to regulatory agencies (e.g., FDA) seeking approval to begin human trials with an experimental drug.

Incentive – Something that supports or encourages research participation.

Incidence – Number of new cases or events during a period of time.

Inclusion criteria – A list of requirements a person must meet to take part in a study.

Informed consent – The process of learning and discussing the details of a research study before deciding whether to take part.

Institutional Review Board (IRB) – A team of people who review studies to protect the rights and welfare of study participants.

Infusion – A way to give a fluid to the study participant, usually through a vein.

Interim Analysis – A planned analysis of data before trial completion.

Interventional study – Also known as a clinical trial, a type of clinical study in which participants receive one or more interventions, according to the protocol and group that they are assigned to, so that researchers can evaluate the effects of the intervention on a health condition.

Indication – A disease, symptom, or particular set of circumstances that make a particular test, medication, procedure, or surgery advisable. For a treatment, an indication refers to the use of that treatment in treating a particular disease.

Investigational drug – The drug being evaluated in the trial; this definition is synonymous with “investigational new drug” or “investigational medicinal product.”

Investigational medicine – A treatment or drug that is not yet approved for the condition being studied.

Investigational New Drug (IND) application – An application to the United States Food & Drug Administration (FDA) to get permission to use a drug in a research study that enrolls people.

Investigational product – A drug, device, vaccine, or other treatment being tested in a study.

Investigator – A person who leads a research study.

IP (Investigational Product) – A pharmaceutical form of an active ingredient being tested in a clinical trial.

IWRS (interactive web response system) – Allows sponsors to proactively manage the key aspects of their clinical trials, including enrollment/randomization, dosing/drug dispensation, clinical supplies, drug inventory management, unblinding, etc.

L

Longitudinal study – Research that collects data from the same participants over a long time.

M

Magnetic Resonance Imaging (MRI) – A way to take pictures of the inside of a person’s body with a machine that uses strong magnets and radio waves.

Master protocol – An overall research plan that guides sub-studies that have their own research questions.

Maximum – The most or largest amount.

MDR (metadata repository) – A database of data about data (metadata). The purpose of the metadata repository is to provide a consistent and reliable means of access to data.

Medication number – A unique number on the label of each investigational drug package that is used in a trial to dispense and track medication. The number is used to make sure the drug is supplied in the right quantities to different research centers.

Mean – The average.

Median – The middle number in a set of numbers when listed in order from lowest to highest.

Minimal – Very small.

Minimum – The smallest or least amount.

Minor – Someone considered too young to give legal consent.

Monitoring – To observe, check, or evaluate something in a study over time.

Morbidity (rate) – The number of people who develop a disease or illness in a group over time.

Mortality (rate) – The number of deaths in a group of people over time.

Multicenter trial – A study that takes place at more than one research center.

N

NDA (New Drug Application) – A formal proposal submitted to regulatory agencies to approve a new drug for market use.

Negative test result – A test result that shows a person does not have what was tested for.

Negligible – So small that it has little to no impact.

Non-compliance – Not following research requirements.

Non-inferiority trial – A study to test if a study treatment works about as well as another treatment for the same condition.

O

Objective – A purpose or goal of a study.

Observational study – A study that collects health information about study participants without giving a treatment.

Observe – To watch or see how participants are doing in a study.

Observational study – An observational study investigates health outcomes amongst groups of people in the course of their everyday life at home, work, or the doctor’s office, where assignment of treatments or other procedures is as part of their regular medical care (not assigned by an investigator).

Occasionally – Once in a while.

Odds ratio – The chance of a health event happening in one group compared with the chance of the same event happening in another group.

ODM-XML – Operational data model – an extended markup language. A vendor-neutral, platform-independent format for exchanging and archiving clinical and translational research data, along with their associated metadata, administrative data, reference data, and audit information.

Off-label – The use of a treatment in a different way or for a condition other than what it is approved for.

Open-label study – A type of study where participants and research staff know which treatment participants are being given.

Orphan Drug – A drug developed for rare diseases affecting a small population.

Outcome (of study) – A description of the overall results of the study.

Outcome measure – The way that a study endpoint is measured.

P

P-value (probability value) – A number that researchers use to show that a result did not occur by chance.

Part – A subdivision of a single protocol into major building blocks. These parts often are independent of each other and have different objectives or different groups of volunteers. For example, a single-dose design and a multiple-dose design may be combined into one protocol (a protocol with two parts) or the same study design could be used with different groups of patients with different severity of a disease.

Participate – To take part in a study.

Patient Reported Outcomes (PROs) – The information that patients share about their own health or well-being to answer questions in a study.

Peer review – Evaluation by independent experts.

Periodically – At regular or expected times.

Pharmacodynamic (PD) study – A study that measures the effects of a drug on the human body.

Pharmacokinetic (PK) study – A study that measures what happens to a drug in a person’s body over time.

Pharmacovigilance – A process to detect, review, and make decisions about drug safety to protect patients.

Phase – Categories, defined by the Food and Drug Administration (FDA), for describing the clinical trial of a drug based on the study’s characteristics, such as the objective and number of participants. There are four phases:

• Phase I trials test an experimental drug, vaccine or device in a small group of people to evaluate safety, identify side effects, and determine safe dosages.
• Phase II trials involve larger groups of people than Phase I and are designed to assess whether an experimental treatment is safe and whether it works. This phase can last several years.
• Phase III trials are usually large studies comparing the experimental drug or vaccine to a placebo or standard treatment, to evaluate whether the drug works and collect information to allow it to be used safely.
• Phase IV trials are performed once a drug has reached the market, to provide additional information about the best use of the drug.

Pilot study – A small study that is done to test a process before starting a larger study.

Placebo – Placebos are inactive substances. In a clinical trial, a placebo, made to look like the investigational treatment, is sometimes used to compare against the actual investigational treatment to evaluate effectiveness.

Placebo-controlled study – A study with two or more groups where one group is given a placebo.

Platform trial – A research study that tests and compares two or more study treatments for a disease or condition, with study treatment groups being added or removed during the study period.

Positive test result – A test result that shows a person has what was tested for.

Post-market surveillance – Continuing to collect and analyze information about the risks and benefits of medicine and devices after they have been approved for patient use.

Post-trial access – When participants can still receive a study treatment after their participation has ended.

Preclinical study – A study to test a treatment in the lab or in animals before testing it in people.

Prevalence – Number of known cases or events in a group.

Primary endpoint – A study measure that is used to answer the main research question.

Principal Investigator – The person who is responsible for the scientific and technical direction of the clinical trial at a specific clinical site. In most cases, the principal investigator will be a leading physician in the disease area being studied.

Probability – The likelihood or chance that something might happen.

Procedures (for participants) – The activities that participants will be asked to do during the research study.

Progression-free survival – The length of time without a person’s illness getting worse.

Prospective study – Research that uses new data collected from participants.

Protocol – A written study plan on which the clinical trial is based. A protocol describes what types of people may or may not participate in the trial; the schedule of tests, procedures, medications, and dosages to be administered; the outcome measures that will be evaluated; and the length of the study.

Proxy – A person who is legally allowed to make research decisions for someone else.

Pseudonymize – Replace personal details with a code so that data are protected.

Purpose – What the study is testing.

Q

Quality of Life (QOL) – How someone feels and functions day to day.

Questionnaire – A list of questions for study participants to answer as part of the study.

R

Randomization – A way to use chance to place study participants into different study treatment groups.

Randomization number – A unique number assigned to each randomized patient that is used to identify individuals but maintain anonymity, corresponding to a specific study arm assignment.

Randomized allocation – A strategy in which participants are randomly assigned to study arms of a clinical trial by computer.

Randomized controlled trial – Research that uses chance to assign participants into study groups.

Rationale – The reason why a study, or something in a study, is being done.

RBM (Risk-Based Monitoring) – A clinical trial monitoring approach that focuses on identifying, assessing, and mitigating risks to ensure data integrity and participant safety. Instead of routine on-site visits, RBM uses centralized monitoring, data analytics, and key risk indicators (KRIs) to detect potential issues early. This method improves efficiency, reduces costs, and enhances trial oversight by prioritizing high-risk areas.

Real World Data (RWD) – Information from many different sources used for health research purposes.

Real World Evidence (RWE) – Findings from analyzing Real World Data.

Registry (study) – An organized list of research information.

Regulatory authority – Government agencies like the FDA or EMA overseeing clinical trials.

Regulatory Submission – The process of submitting necessary documents, such as clinical trial protocols, data, and investigational product information, to regulatory authorities for approval.

Reimburse – Pay money back to participants for their out-of-pocket study costs.

Relative risk – The chance of a harmful event happening in one study group compared with another.

Repository (research) – A collection of participant data and samples stored for future research.

Results (study) – Findings from the study.

Retrospective study – Research that uses already existing data.

Risk-benefit ratio – A comparison of the possible bad and potential good things that could happen if a participant joins a research study.

Risks of a research study – The possible harms of being in a research study.

Run-in period – The elapsed time before a trial starts when no investigational drug is given to trial participants. During this time, patients may still receive standard treatments for their disease if these treatments are allowed within the trial period.

S

SaaS (software as a service) – A method of software delivery that allows data to be accessed from any device with an Internet connection and web browser. In this web-based model, software vendors host and maintain the servers, databases, and code that constitute an application.

Safety Reporting – The process of notifying regulatory authorities, sponsors, and ethics committees about adverse events or side effects occurring during a clinical trial.

SAP (Statistical analysis plan) – The written description of the statistical considerations and methods for analyzing the data collected in the clinical study.

SaS (statistical analysis system) – A software suite developed by SAS Institute for advanced analytics, multivariate analysis, business intelligence, data management, and predictive analytics.

Sample size – The number of participants in a study or study group.

Schedule of assessments – A chart that lists the study activities and when they will happen during a study.

Screening – Tests and questions to find out if a person can join a study.

SDTM (Study Data Tabulation Model) – A standard for organizing and formatting data to streamline processes in the collection, management, analysis, and reporting. It is the format required for submission of clinical data to the US FDA and Japan’s PMDA (Pharmaceuticals and Medical Devices Agency).

Secondary endpoint – A measure used to answer other important questions in the study that are not the main research question.

Sensitivity (medical test) – How well a medical test can accurately identify people who have a disease or trait.

Sequential – Happening in a specific order.

Serious adverse event (SAE) – An adverse event that is life-threatening, requires hospitalization or extended hospital stay, results in ongoing or significant incapacity, causes congenital anomalies or birth defects, or results in death.

Side effect – A health change that is not the intended effect of the treatment and usually considered a problem.

Single-blind study – A study that is set up so that the study treatment each participant receives is not known by the participants but is known by the researchers.

SOP (Standard Operating Procedure) – Detailed, written instructions to ensure consistency in clinical trial operations, regulatory compliance, and safety protocols.

Source Data – Original records where clinical trial data is first recorded.

Specificity (medical test) – How well a medical test can accurately identify people who do not have a disease or trait.

Sponsor – The group that is in charge of, or pays for, a research study.

Standard of care – The usual treatment given to patients for an illness.

Standard Operating Procedures (SOPs) – Written guidelines for conducting clinical research activities.

Statistically significant – Results that are very unlikely to have occurred by chance.

Study completed date – The date on which the last trial participant made the final visit to the study location (that is, “last subject, last visit”) and the last samples were collected or last tests performed.

Study design – The way a study is set up to answer the study question.

Study feasibility – How likely it is that a study can be completed.

Study intervention – A treatment given to the participants in a study.

Study life cycle – The steps of a research study from beginning to end.

Study participant – A person who joins a research study.

Study population – All the participants in a study.

Study statistician – A person who uses math to help design a study and interpret the data.

Substudy – A study with a smaller group of participants already enrolled in the main study.

Superiority trial – A study to test if a study treatment works better than another treatment for the same condition.

Subject – An individual (either a healthy volunteer or a patient volunteer) whose reactions or responses to certain interventions are evaluated during a clinical trial. May also be referred to as a trial participant.

Subject number – A unique number assigned to each participant who enrolls into a clinical trial.

Subject Withdrawal – When a participant leaves a trial before completion.

Synergistic effect – When two or more things combined have a greater effect than when their individual effects are added together.

T

Tolerability – How much a participant or group of participants can accept a study treatment’s unwanted effects so they can keep taking it.

Treatment Arm – A group of participants receiving a specific intervention in a trial.

Treatment effect – How much a study treatment changes a condition, symptom, or function.

U

UAT (user acceptance testing) – The last phase of the software testing process when actual software users test the software to make sure it can handle required tasks in real-world scenarios, according to specifications.

Umbrella trial – A research study that tests and compares two or more study treatments for one disease or condition.

V

Validate – To confirm that a process or test works as planned, or results are true.

Voluntary participation – Choosing to participate in research without feeling pressured.

Volunteer (to) – To choose to join a study.

Variable – Information collected during a clinical trial either from direct or indirect data. For example, one variable might be “weight,” which would then be checked at specified time points throughout the trial.

W

Wash-out – A time before starting a study treatment when a person stops taking other medicines.

Wash-out period – The period of time allowed for all of the administered drugs to be eliminated from the body.

Withdraw – To stop being a participant in a study.