Table 3.

Test-retest Correlations for 30 and 90 Day Time Intervals

	Raw Dataa				Trimmed Datab		Reduced Datac
Items	0–30 days prior	31–60 days prior	61–90 days prior	0–90 days prior	0–30 days prior	0–90 days prior	0–30 days prior	0–90 days prior
Maximum drinks	.93 (58)	.82 (59)	.92 (59)	.97 (70)	.88 (58)	.92 (70)	.78 (56)	.90 (67)
Total drinks	1.00 (58)	.99 (59)	1.00 (59)	1.00 (70)	.98 (58)	.99 (70)	.91 (55)	.95 (68)
Drinking days	.99 (58)	.95 (59)	.92 (59)	.97 (70)	.98 (58)	.97 (70)	.93 (53)	.88 (65)
Heavy drinking days	.73 (37)	.72 (41)	.68 (42)	.77 (51)	.68 (37)	.76 (51)	.73 (34)	.84 (48)
Marijuana use days	.94 (37)	.88 (33)	.84 (35)	.91 (44)	.94 (37)	.91 (44)	.92 (28)	.88 (35)
Composite drug use days	.94 (25)	.94 (30)	.90 (31)	.94 (38)	.92 (25)	.94 (38)	.88 (23)	.90 (36)
Drug or alcohol use days	.97 (75)	.95 (71)	.92 (73)	.96 (83)	.97 (75)	.96 (83)	.91 (53)	.94 (64)

Note. Pearson correlations were computed omitting participants who reported no use at both occasions. Time intervals are based on the number of days prior to the first data collection. Adjusted sample sizes are in parentheses.

^aPearson correlations computed including all cases.

^bPearson correlations computed on data where outliers were reduced to three standard deviations from the mean.

^cPearson correlations computed with extreme raw scores omitted.