The different types of clinical trials can vary by objective, design, and number of participants, as well as other factors. They can be categorized by purpose, which vary in both design and goals, depending on what researchers are trying to find out. Clinical trials also can be broken down by phases, ranging from preclinical to post-marketing, depending on what stage of the research process a treatment or intervention is in at a given time.

Clinical trials are usually the culmination of several years spent developing new therapies and approaches in research laboratories. Researchers must create a plan, called a protocol, that details how they will explore the effects of their proposed intervention in a human population, including the length of the trial, eligibility requirements, any necessary tests and procedures, and the specific outcomes to be measured.

Thanks to advances in digital technology and telemedicine, there are now more options for how — and where — clinical trials are conducted. Remote clinical trials take place in a virtual environment with participants joining by using mobile phones, computers, or other devices, while traditional clinical trials take place in person at a research site. A hybrid approach combines remote and in-person aspects.

Looking for some quick answers to your questions on clinical trials? Check out our FAQs page for more information on clinical trials, how they work, their risks and benefits, and factors to consider before deciding to participate in clinical trials.