“…This null finding is puzzling but not altogether surprising. As the medical literature shows, at a minimum, knowing a trauma center's startup date is important; for many years after implementation, individual centers may become "magnets" for trauma cases with high fatality rates, channeling and concentrating their distribution from previously broader, regional dispersions (Hammond & Breckenridge, 1999;Nathens et al, 2000;O'Keefe et al, 1999). In estimating trauma center effects, it would also be helpful to know which level of trauma care these trauma centers represent, and whether and how they are certified.…”