What’s the Difference Between an Observational Trial and an Interventional Trial?

Posted by: My Kidney Research

DaVita Clinical Research

It may be confusing to know what types of clinical studies and trials participants should pursue, or even what the difference is between the many different clinical research terms. What’s the difference between an observational trial and an interventional trial?


Here’s what you need to know before you sign up.

Different Types of Clinical Trials

Clinical research terminology can often get confusing. Here are two of the most common types of clinical trials:

Observational study

A clinical study in which participants identified as belonging to study groups are assessed for biomedical or health outcomes. Participants may receive diagnostic, therapeutic, or other types of interventions, but the investigator does not assign participants to specific interventions (as in an interventional study)


Interventional study

A clinical study in which participants are assigned to receive one or more interventions (or no intervention) so that researchers can evaluate the effects of the interventions on biomedical or health-related outcomes. The assignments are determined by the study protocol. Participants may receive diagnostic, therapeutic, or other types of interventions.


Inpatient vs. Outpatient

There are various lengths of time for different clinical studies and trials. Just like with other medical services, outpatient procedures generally refer to when the participant only stays a short time in the facility. Inpatient trials usually refer to those that require a longer stay which could be overnight or for multiple days.


Find out more

You can find out more information about both clinical studies and individual trials that you can participate in by visiting DaVita Clinical Research (DCR) or talking with a DCR recruiter. To find out more information about clinical studies and clinical trials, and how you can get started, get in contact with a DCR recruiter today.


Disclaimer: Phase 1 (in-patient) clinical trials are not intended to treat a disease or condition. Phase 3 (out-patient) clinical trials may help treat an existing disease or condition. The information presented in this blog may be referring to either a phase 1 clinical trial or to a phase 3 clinical trial or to both. If you contact us regarding a trial, be sure to speak with the recruiter about whether or not the trial is intended to treat a condition.