Why naval-infantry casualty comparisons need unit-level evidence

How did naval-infantry casualty rates compare with regular infantry in the First World War and in the Russia-Ukraine war?

British Royal Marines were broadly comparable with regular infantry over the First World War, while the panel does not claim a reliable aggregate modern Russian percentage and instead notes severe unit-level losses.

The answer puts Royal Marines casualty rates across the First World War at about the same level as regular British infantry, despite their training and experience. No comparable figure is offered for Russian naval infantry in that war. For the Russia-Ukraine war, Clarke instead reports naval-infantry units destroyed and raised again. He links some of that knowledge to an international network of former students, including people who have stopped communicating. This is a personal and incomplete account of severe unit losses, without an aggregate casualty percentage.