From a victim's physical health perspective, at the centre of any case of intimate partner violence (IPV) is the degree of trauma imparted on that victim by the offender. Yet, the implementations of state-level 'Mandatory Arrest' and 'Preferred Arrest' laws encourage arrests decisions in cases of IPV typically without regard to the level of trauma severity found in each case. And, despite these well-meaning implementations and the gravity of their consequences, the importance of evaluating trauma severity in victims of IPV remains largely overlooked. The goal of this study was to correlate police arrest decisions in cases of IPV to a trauma severity score generated from established clinical protocols in the treatment of trauma. A Trauma Severity Quantification Table (TSQT) was created in order to quantify the major factors of an incident of IPV: anatomical location of attack, method of attack, facilitating weapon/object and resulting trauma. A total of 256 cases of IPV reported to six police departments in Idaho, a state with a discretionary arrest law in domestic violence cases, in the calendar year 2000 were processed using the TSQT. A statistically significant difference was found between arrests (mean 17.96, standard deviation [SD] 5.90) versus no arrest (mean 16.13, SD 5.67) outcomes (P = 0.03). It is suggested that trauma severity is a factor in police arrest decisions in a discretionary state sample, but that more attention needs to be brought to this method of analysis and its implications for future arrest decisions.