Estimated Number of People Needed

0
,
0
0
0
,
0
0
0

to fulfill demand among all enrolling studies on clinicaltrials.gov *

That's about 1 in 6 U.S. citizens 1

* The data set used to present this information has been altered. Learn more.
People who participate in clinical research studies are called “study volunteers” or “research participants.” For the purposes of this presentation, we will call them “participants” throughout. Clinical research studies fall into two major design categories. These design types have different enrollment needs.

Interventional Studies

In interventional studies, also called clinical trials, participants are assigned specific interventions according to a research plan, or protocol, created by researchers. These interventions can be procedures, changes to behavior like diet, or medical products like drugs or devices. Clinical trials used to develop drugs, medical devices, and other treatments are often described using a phase number. 2

Observational Studies

In observational studies, participants are seen in their actual medical practice setting and may or may not receive an intervention. When an observational study does have an intervention, it is not assigned by a research protocol as in an interventional study. For example, researchers may observe older adults to learn about the effects of different lifestyles on cardiac health. 2

How Many Total Participants are Needed by Study Phase?

For the remainder of this presentation, we focus on Interventional studies, which are usually assigned a study phase. Phase 1 through 3 trials are necessary for the development of potential new treatments. Phase 4 trials answer additional efficacy and safety questions for treatments available on the market. The current number of participants needed to enroll in Phase 3 Interventional trials is roughly equal to the population of Chicago. 5 Learn how we are summarizing the data.
20
40
60
80
100
  • Estimated Number of Participants Needed to Enroll in Interventional Studies
  • Number of Participants Needed

How Many Participants are Needed for Various Diseases?

The bars below show the number of participants needed in Interventional studies currently open for enrollment. For research studies on common conditions to move forward and provide new treatments, they need participants to volunteer. If you are interested in learning more about clinical trials, you can visit clinicaltrials.gov. Learn how we are summarizing the data.
Autoimmune Disorders
Bone Disease
Cancer
Cardiovascular Disease
Diabetes
Mental Health
20
40
60
80
100
  • Estimated Number of Participants Needed, by Condition
  • Phase 1
  • Phase 2
  • Phase 3
  • Phase 4