What are “eligibility criteria”?
All trials have guidelines about who can take part. These are called 'eligibility criteria', consisting of inclusion criteria (i.e. who is suitable to participate) and exclusion criteria. Not anyone who suffers from a particular disease can take part in any trial that studies this disease: the eligibility criteria for a lung cancer trial for instance might say that the only people who can take part are people who are at the earliest stages of their condition, who are over 18 but under 80, and who have no other health problems.