Table 1.

Creation of dichotomous latent class indicators and covariates

	Code	Label	Frequency (valid %)
Indicator variables
Internal protective factors
Life satisfaction	1	Inadequatea	2,237 (21.8%)
	2	Adequate	6,986 (67.9%)
		Missing	1,064 (10.3%)
Planful competence	1	Inadequatea	2,231 (21.7%)
	2	Adequate	7,833 (76.1%)
		Missing	223 (2.2%)
Physical activity	1	Inadequateb	2,610 (25.4%)
	2	Adequate	7,633 (74.2%)
		Missing	44 (0.4%)
Positive school orientation	1	Inadequatea	2,483 (14.1%)
	2	Adequate	7,772 (75.6%)
		Missing	32 (0.3%)
External protective factors
Parents’ monitoring/limit-setting	1	Inadequatea	2,004 (19.5%)
	2	Adequate	6,016 (58.5%)
		Missing	2,267 (22.0%)
Parent–child communication	1	Inadequatec	2,105 (20.5%)
	2	Adequate	5,871 (57.1%)
		Missing	2,311 (22.5%)
Low friends’ ATOD use	1	Inadequatea	2,393 (23.3%)
	2	Adequate	7,321 (71.2%)
		Missing	573 (5.6%)
Other adult communication	1	Inadequatec	1,871 (18.2%)
	2	Adequate	6,100 (59.3%)
		Missing	2,316 (22.5%)
Substance use behaviors covariates
Lifetime alcohol use	1	Use	5,025 (48.9%)
	2	Non-use	5,262 (51.2%)
30-day alcohol use	1	Use	7,702 (74.9%)
	2	Non-use	2,585 (25.1%)
Lifetime cigarette use	1	Use	7,164 (69.6%)
	2	Non-use	3,123 (30.4%)
30-day cigarette use	1	Use	9,144 (88.9%)
	2	Non-use	1,143 (11.1%)

^aThe standardized indicator was dichotomized using quartiles: bottom 25% (inadequate) and top 75% (adequate)

^bThe original (single-item) five-point response scale was dichotomized such that physical activity once or twice a month, a few times a year, or never was coded as inadequate and activity at least once a week or almost every day was coded as adequate

^cThe original (single-item) three-point response scale was coded: no (inadequate) and some, most or all (adequate).