Table 4.

Item-response probability and class prevalence rates for students at 4-year institutions

	Latent Class
Past Month Alcohol and Marijuana Indicators	Non-users (9%)	Light- drinking- only (26%)	Heavy drinking/light marijuana/SAM use (32%)	Heavy- drinking-only (33%)
Any drinking	0.000	1.000	1.000	1.000
Binge drink	0.000	0.067	0.789	1.000
Peak eBAC > .08	0.000	0.172	0.824	0.946
Alcohol problems	0.000	0.632	0.947	0.952
SAM use	0.000	0.000	0.888	0.000
Marijuana use	0.094	0.155	1.000	0.191
Marijuana use > 1 time/day	0.031	0.000	0.346	0.000
Marijuana use of getting high > 15 days	0.000	0.009	0.294	0.000

Note. All indicators assessed alcohol and marijuana use in the past month; eBAC = estimated blood alcohol concentration; SAM = simultaneous alcohol and marijuana use; Bold = class-defining probabilities