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Helpful Terminology

Clinical Trial Status

It is important to know if a study is in the planning, active, or completed stages. When you are looking for clinical trials, you want to pay particular attention to those that are “recruiting.” Here is more information about these terms: 

  • Active, not recruiting: The study is ongoing, and participants are receiving an intervention or being examined, but potential participants are not currently being recruited or enrolled. 

  • Completed: The study has ended normally, and participants are no longer being examined or treated (that is, the last participant's last visit has occurred). 

  • Enrolling by invitation: The study is selecting its participants from a population, or group of people, decided on by the researchers in advance. These studies are not open to everyone who meets the eligibility criteria but only to people in that particular population, who are specifically invited to participate. 

  • Not yet recruiting: The study has not started recruiting participants. 

  • Recruiting: The study is currently recruiting participants. 

  • Suspended: The study has stopped early but may start again. 

  • Terminated: The study has stopped early and will not start again. Participants are no longer being examined or treated. 

  • Unknown: The study is considered closed since the trial status has not been verified for at least 2 years. 

  • Withdrawn: The study stopped early, before enrolling its first participant.  

Study Type 

When looking for a clinical study, it is important to understand the different types of studies, and know the type of study you are looking for: 

  • Interventional Study: A type of clinical study in which participants are randomly assigned to either the intervention group, or the control group so that researchers can evaluate the effects of the treatment being studied. 

                     
    • Intervention Group: participants receive the treatment being studied. Participants may receive diagnostic, therapeutic, or other types of interventions. 
 
    • Control Group: participants may receive the standard of care.
 
    • Standard of Care: either receiving a previously approved medication, or no medication, according to the disease treatment guidelines.
  • Observational Study: A type of clinical study in which specific groups of people are recruited to participate, based on certain shared characteristics. Participants may receive diagnostic, therapeutic, or other types of interventions, but the researchers do not assign participants to a specific treatment. Without changing any parts of the participants’ medical/treatment routine, researchers assess participants’ health outcomes. 

  • Expanded Access (Compassionate Use): This is a way for patients with serious diseases or conditions who cannot participate in a clinical trial to gain access to a medical product that has not been approved by the Food and Drug Administration. It is also called compassionate use. Regulations regarding this type of access are strict and may differ according to the country.  

  • Cohort Study: A type of medical research used to investigate the causes of disease, establishing links between risk factors and health outcomes. These studies are usually prospective, meaning they are planned in advance and conducted over a future period of time. 

Other Important Terms

  • Protocol: The plan for how a clinical trial will be conducted, its goals, design (including eligibility criteria and how participants will be randomized into the intervention or control group), and methods (how the treatment will be administered, how data will be collected and analyzed, etc.).  

                   
    • The protocol also outlines how the study will ensure potential participants are aware of the entire process before agreeing to participate (informed consent), and how it will protect participants’ safety during the study. 

  • Institutional Review Boards (IRB): Review the study protocol to make sure the risk of harm to participants is low, and any potential harms are a reasonable part of the study. They also make sure the research team has measures in place to mitigate the risk of harm and to protect participants’ privacy. 

                   
    • Also known as “Ethical Review Boards (ERB),” “Independent Ethics Committees (IEC),” “Research Ethics Board (REB)” 

  • Eligibility criteria - These are requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Some studies will list both “inclusion” criteria, and “exclusion” criteria. Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by gender. 

  • Anonymity: Participants in clinical trials are not identified by name. 

  • Blinding: Participants are assigned to either the intervention or control group, but are blinded to their assignment, meaning, they do not know which group they are in. 

  • Dosing level: Amount of treatment given to participants in the intervention group. 

  • Effectiveness: How well the treatment works in practice.

  • Exclusion Criteria: Certain characteristics which prevent a person from participating(for example: pregnancy, having other diseases or infections) 

  • Inclusion Criteria: Certain characteristics that are required for a person to participate in the study (for example: age, disease stage) 

  • Informed Consent: A form that potential participants must read and sign prior to joining the clinical trial, to acknowledge and confirm their understanding of what is involved in study participation. 

  • Randomization: a process where participants in clinical trials are assigned by chance (randomly) to either the intervention group, or the control group.  

For a full list of terms, you can visit the clinicaltrials.gov glossary. 

*Terminology was referenced from clinicaltrials.gov