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. Author manuscript; available in PMC: 2018 May 1.
Published in final edited form as: Drug Alcohol Depend. 2017 Mar 7;174:150–157. doi: 10.1016/j.drugalcdep.2017.01.025

Table 4.

Results from a trend analysis of opportunity and use given opportunity over all seven years of study

Opportunity Use Given Opportunity
Marijuana Other Drugs Prescription Medications Marijuana Other Drugs Prescription Medications
Linear −0.24 (0.009)* −0.15 (0.008)* −0.30 (0.008)* −0.20 (0.018)* 0.02 (0.025) −0.02 (0.027)
Quadratic −0.02 (0.006)* −0.05 (0.006)* 0.00 (0.007) 0.02 (0.014) −0.01 (0.022) −0.03 (0.023)
Cubic 0.05 (0.006)* 0.02 (0.006)* 0.06 (0.006)* 0.02 (0.012) 0.04 (0.019)* −0.03 (0.022)
Order 4 0.01 (0.006) −0.01 (0.005) −0.02 (0.006)* −0.02 (0.011) 0.04 (0.019)* −0.05 (0.022)*
Order 5 −0.01 (0.005) −0.02 (0.005)* 0.01 (0.006)* −0.01 (0.012) 0.02 (0.017) 0.00 (0.019)
Order 6 0.01 (0.005) 0.01 (0.005) −0.02 (0.006)* −0.01 (0.011) 0.02 (0.016) 0.00 (0.018)
*

Significant at the p<0.05 level.

Note. Values are polynomial contrast estimates and the associated standard errors using maximum likelihood estimation, the log link function, robust errors, and Huber-White sandwich estimators. Prescription medications represent opportunity and use given opportunity of nonmedical use of prescription stimulants, analgesics, and tranquilizers only.