Regarding Žerjavić's research on World War Two casualties, Croatian historian Vladimir Geiger notes that individual researchers who assert the inevitability of using identification of casualties and fatalities by individual names have raised serious objections to Žerjavić's calculations/estimates of human losses by using standard statistical methods and consolidation of data from various sources, pointing out that such an approach is insufficient and unreliable in determining the number and character of casualties and fatalities, as well as the affiliation of the perpetrators of the crimes.