Two predicted continuous volume variables were then created for each patient, one corresponding to the patient’s BAC from the empirical fractional polynomial regression equation, another from inserting the BAC into the Widmark equation. These two relationships were then inverted to obtain V^E andV^W. The empirical BAC estimate was used along with Table 1 in order obtain a corresponding estimate of the volume bin. The continuous volume estimate from the inverted Widmark equation was also categorized corresponding to the volume bin cutpoints in Table 1. In this way, the self-reported categorized volume could be compared directly to either the categorized volume from the empirical regression estimation or from Widmark’s equation.
