Table 1.

Descriptive statistics comparing types of measurement

Variable	M	SD	Range
Drinks per day (Level 1)a
Diary drinks per day	0.97	2.67	0–25
Followback drinks per day	1.08	2.59	0–25
Difference of diary and Followback	−0.13	2.40	−19–25
Maximum drinks (Level 2)b
Diary maximum drinks	7.45	5.00	1–25
Followback maximum drinks	6.97	4.26	1–25
Retrospective maximum drinks	7.30	4.37	0–25
Frequency of heavy drinking (>5) in last 2 weeks (Level 2)b
Diary heavy drinking days	2.54	2.79	0–13
Followback heavy drinking days	1.41	1.73	0–7
Retrospective heavy drinking occasions	1.22	1.52	0–10

Notes:

^an = 176 students on N = 4,579 person-days;

^bn = 161.