What is a clinical trial?

A clinical trial is fundamentally defined as a study that involves human subjects to evaluate the safety, effectiveness, and side effects of therapeutic agents. This definition encompasses a wide range of research types but is primarily focused on testing new drugs, medical devices, or treatment protocols in real-world conditions to determine their efficacy compared to standard treatments or control groups.

In a clinical trial, researchers gather data on how participants respond to a specific therapy, which can involve direct measurement of health outcomes. The trials are usually conducted in phases, each with a specific goal, such as determining the optimal dose, assessing side effects, or comparing the new treatment against a placebo or existing treatments.

The other choices do not capture the essence of what constitutes a clinical trial. For example, while a treatment using a placebo may be a component of some clinical trials (particularly in randomized controlled trials), it does not define a clinical trial, which encompasses broader research involving various therapeutic agents. Methods for patient diagnosis and surveys of patient satisfaction are important aspects of healthcare but do not involve the rigorous testing of therapeutic interventions that is central to clinical trials.