Table 3.

Estimated Effect of Age 19/20 Frequency of Marijuana Use on Two-Year Degree Attainment by Age 23/24 years (Full Longitudinal Sample): Logistic Regression and Propensity Score Analyses

	Estimated Proportion with Bachelor’s degree or higher
	No/Less Use	More Use	z	p
Non-Users vs Infrequent Users (n=4,466)
Logistic regressions
No Controls	0.529	0.533	−0.17	0.868
With age 18 risk factor controls	0.533	0.522	0.33	0.742
With age 18 risk factor + SUa controls	0.531	0.532	−0.04	0.967
Propensity models
Matched on age 18 risk factors	0.649	0.552	−3.17	0.002
Matched on age 18 risk factors + SU	0.571	0.552	−0.54	0.586
Non-Users vs Frequent Users (n=4,452)
Logistic regressions
No Controls	0.529	0.426	3.63	0.000
With age 18 risk factor controls	0.529	0.437	2.70	0.007
With age 18 risk factor + SUa controls	0.526	0.461	1.50	0.135
Propensity models
Matched on age 18 risk factors	0.514	0.447	−2.01	0.045
Matched on age 18 risk factors + SU	0.486	0.447	−0.92	0.358
Infrequent Users vs Frequent Users (n=932)
Logistic regressions
No Controls	0.533	0.426	2.87	0.004
With age 18 risk factor controls	0.516	0.443	1.72	0.085
With age 18 risk factor + SUa controls	0.496	0.440	1.18	0.237
Propensity models
Matched on age 18 risk factors	0.466	0.447	−0.50	0.620
Matched on age 18 risk factors + SU	0.399	0.447	0.84	0.401

^aAge 18 risk factor controls: gender, race/ethnicity, parent education, family structure, region of country, public high school, college prep curriculum, grade point average, academic ability, 4-yr college plans, other post-high-school training plans, hours worked for pay, evenings out, and truancy.

^bSU=Substance use: Age 18 30-day tobacco use, alcohol use and marijuana use.