Inclusion and exclusion criteria

What does Inclusion and exclusion criteria mean in clinical research?

Federal regulations for ClinicalTrials.gov define eligibility criteria as a limited list of criteria for selecting human subjects to participate in a clinical trial, provided as inclusion and exclusion criteria.^⁠[1] Inclusion criteria describe who the study needs, such as diagnosis, disease stage, age or lab ranges. Exclusion criteria describe who must be left out, usually for safety or to keep the results interpretable.

Criteria also drive screen failure. In an audit of 15 randomized oncology studies at a cancer center in India, not meeting inclusion criteria was the most common reason, accounting for 54.9% of screen failures.^⁠[2] Protocols are also getting harder to match: Tufts CSDD benchmarks show Phase II and III protocols averaging more eligibility criteria than before.^⁠[3]

Practical note: before outreach, sort each criterion by where it can be settled:

• In the chart, such as diagnosis, stage, prior therapy and recent labs. Identify evaluates these and shows the evidence.
• On a short call, such as willingness to travel or current medications.
• Only at the screening visit, such as protocol-specific labs or imaging.