Episode 19 of CRAMSURG - Clinical Reasearch Appraisal and Methodology for Surgical Trainees. The paper for discussion is Prophylactic sublay non-absorbable mesh positioning following midline laparotomy in a clean-contaminated field: randomized clinical trial (PROMETHEUS), British Journal of Surgery Apr 2021, the teaching topic is problems with multiple statistical testing. Brought to you by CRAMSURG www.cramsurg.org.