Objective-To quantify sensitivity of various biomechanical measures of head impact (linear acceleration, rotational acceleration, impact duration, impact location) to clinical diagnosis of concussion in American football players and to develop a novel measure of head impact severity which combines these measures into a single score that better predicts the incidence of concussion.Methods-On-field head impact data were collected from 449 football players at 13 organizations (n = 289,916) using in-helmet systems of six single axis accelerometers. 1,2,3,4,5 Concussions were diagnosed by medical staff and later associated with impact data. Principal Component Analysis 6, 7 and a weighting coefficient based on impact location were used to transform correlated head impact measures into a new composite variable (wPCS). The predictive power of linear acceleration, rotational acceleration, Head Injury Criteria, and wPCS was quantified using Receiver Operating Characteristic 8,9,10 curves. The null hypothesis that a measure was no more predictive than guessing was tested (α=0.05). Additionally, ROC curves for wPCS and classical measures were directly compared to test the hypothesis that wPCS was more predictive of concussion than classic measures (α=0.05).Results-When all impacts were considered, every biomechanical measure evaluated was statistically more predictive of concussion than guessing (p < 0.005). However, for the top 1% and 2% of impacts based on linear acceleration, a subset that consisted of 82% of all diagnosed concussions, only wPCS was significantly more predictive of concussion than guessing (p<0.03), and, when compared to each other, wPCS was more predictive of concussion than classical measures for the top 1% and 2% of all data (p < 0.04).Conclusions-A weighted combination of several biomechanical inputs, including impact location, is more predictive of concussion than a single biomechanical measure. This study is the first to quantify improvements in the sensitivity of a biomechanical measure to incidence of concussion when impact location is considered.