Table 2.

Descriptive statistics for change scores and discrepancies between W3-W4 prospective and W4 retrospective change scores, N=1,082

	Cigarettes	E-cigarettes	Marijuana	Alcohol
Continuous Prospective W3-W4 Change Score, M (SD)	0.51 (8.74)	1.96 (9.00)	2.24 (8.12)	2.20 (5.92)
Categorical Prospective W3-W4 Change, N (%)
Increased	94 (43.3)	110 (41.7)	203 (52.6)	430 (55.6)
Decreased/Same	123 (56.7)	154 (58.3)	183 (47.4)	344 (44.4)
Categorical Retrospective Self-Report Change, N (%)
Increased	62 (32.5)	84 (31.2)	212 (53.5)	440 (53.8)
Decreased/Same	129 (67.5)	185 (68.8)	184 (46.5)	348 (44.2)
Discrepancies in W3-W4 Prospective and Retrospective Change Scores, N (%)
Increased W3-W4 and Retrospective Self-Report (Increaser)	24 (13.5)	34 (13.8)	116 (31.4)	288 (38.7)
Decreased/Same W3-W4 and Retrospective Self-Report (Decreaser)	73 (41.0)	103 (41.9)	93 (25.2)	195 (26.2)
Decreased/Same W3-W4 but Increased Retrospective Self-Report (Over-reporter)	34 (19.1)	43 (17.5)	82 (22.2)	130 (17.4)
Increased W3-W4 but Decreased/Same Retrospective Self-Report (Under-reporter)	47 (26.4)	66 (26.8)	78 (21.1)	132 (17.7)

Note: Analyses conducted among W4 users of respective substances (N=233 for cigarettes, N=288 for e-cigarettes, N=414 for marijuana, N=818 for alcohol).