Table 1 lists variables drawn from four domains of specific relevance to the present analyses: demographics, risk factors, R/S variables, and alcohol milestones. Variables were constructed (a) consistent with their original form as continuous, rank ordered, or dichotomous variables, and (b) after transformation to dichotomous form (to correct for normality and linearity violations observed in the original variables). Both formats were analyzed, and highly similar results were obtained. This was because the standard procedures for correcting violations of the Proportional Hazards (PH) assumption in Cox PH survival analyses (see Data Analysis) adjusted similar features of the data as are addressed with dichotomous transformation. Thus, both approaches yielded essentially equivalent results. The results reported here are from analyses based on dichotomous variables since these results were slightly more conservative.
