Two studies of motor vehicle injury patients in trauma centers which analyzed the relationship of self-reports of the number of drinks consumed with serum BAC found only moderate correlations, r=0.43 (Sommers et al., 2000) and r=0.26 (Sommers et al., 2002). In each study, self-reported volume underestimated BAC on average indicating that patients either under-reported the number of drinks consumed or overestimated the amount of time spent drinking. Other, non-ED based, studies have also found poor correlation of reported volume of consumption with BAC. A study of college students found a general over-reporting of drinking, with BAC inversely related to the likelihood of over-reporting (Kraus et al., 2005). Another college student drinking study found that while estimated BAC from self-reported volume and BAC estimated from breath analysis were highly correlated (r=.84), at higher breath analysis levels (> 0.08%) the relationship was no longer significant (r=0.23) (Carey and Hustad, 2002).
