Table 3.

Descriptive statistics for prospective and retrospective assessments of the quantity-frequency index measure for the entire sample and the 420 lifetime alcohol-dependent men

Prospective reports				Retrospective reports
Year and assessment	n	Median	Mean (SD)	Year in LDH	n	Median	Mean (SD)	r†
Entire sample
1987 SOHb§	1,288	7.0	30.0 (50.5)	1987	1,290	8.0	37.8 (69.5)	.60
1990NHLBI	1,183	6.5	30.2 (54.0)	1990	1,201	8.0	33.5 (64.6)	.63
1992 HDSb§	1,295	4.3	22.3 (46.3)	1992	1,291	6.0	34.0 (67.3)	.63
1995 HSUSb	849	5.0	26.6 (50.2)	1995	858	6.0	34.0 (66.1)	.69
Non-alcohol- dependent sample
1987 SOH*	873	0.0	23.6 (42.3)	1987	870	4.5	20.9 (41.0)	.59
1990 NHLBI§	798	6.5	23.1 (41.0)	1990	810	4.0	19.5 (39.1)	.62
1992 HDSa§	875	0.0	15.9 (33.0)	1992	871	4.0	20.1 (41.3)	.60
1995 HSUS	511	4.0	22.3 (42.1)	1995	517	6.0	22.0 (39.2)	.69
Lifetime alcohol-dependent sample
1987 SOHb§	415	17.2	43.7 (62.5)	1987	420	30.0	72.9 (97.7)	.57
1990 NHLBIb§	385	12.9	44.9 (71.8)	1990	391	24.0	62.7 (91.8)	.63
1992 HDSb§	420	8.6	35.5 (63.8)	1992	420	16.0	62.9 (95.7)	.66
1995 HSUSb§	338	6.5	33.1 (59.9)	1995	341	8.0	52.2 (90.1)	.69

Notes: LDH = Lifetime Drinking History administered as part of the Family Twin Study. r = correlation (between retrospective and prospective reports of consumption); SOH = Survey of Health; NHLBI = National Heart, Lung, and Blood Institute; HDS = Harvard Drug Study; HSUS = Health Services Utilization Survey.

^a p < .01,

^b p < .001, when comparing retrospective to prospective mean via t test;

^* p < .05,

^§ p < .001, when comparing retrospective to prospective median via Wilcoxon Signed Rank Test.

^†The correlations between retrospective LDH and prospective assessment scores were calculated using log-transformed scores. All correlations were significant at p< .01.