Screening is real work
Pre-screening, labs, imaging, eligibility review and site staff time all happen before a participant is randomized or dosed.
Small eligibility changes can matter
A criterion that removes a large fraction of otherwise suitable patients may be scientifically necessary, or it may be legacy complexity worth challenging.
Model the screened population
If you need 100 enrolled patients and 50% fail screening, you need roughly 200 successful screens before accounting for other losses.
Questions people actually ask
FAQ
Is 30% screen failure high?
It can be material, but whether it is acceptable depends on the disease, biomarker and screening burden.
Can eligibility criteria be simplified?
Sometimes, but only after clinical, safety, statistical and regulatory review.
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