Table 3.

Percentages of Collateral Underestimates, Same Estimates, and Overestimates Based on Wilcoxon Signed Rank Tests

Substance use variable	Collateral underestimate	Collateral same estimate	Collateral overestimate	n
Total no. of drinks	61	22	17	157
No. of drinking days	59	24	17	167
No. of heavy drinking days	49	35	16	164
Ave. drinks per drinking day	68	0	32	57
Ave. drinks per day	61	21	18	161
No. of days used any illicit drugs	58	32	10	162
No. of days used marijuana	25	69	6	154
No. of days used cocaine/crack	44	46	10	157

Note. Collateral underestimate = collateral < subject; collateral same estimate = collateral–subject tie; collateral overestimate = collateral > subject. Data in the last column represent the number of subject–collateral pairs. Ave. = average.