Portland State University, Graduate School of Education, Portland, OR 97201, USA.
J Subst Abuse Treat. 2013 Nov-Dec;45(5):426-32. doi: 10.1016/j.jsat.2013.05.011. Epub 2013 Jul 26.
This study analyzes data on 7661 individuals who participated in the 1979 National Longitudinal Survey of Youth (NLSY79) to estimate trajectories of employment and marijuana-use over a 17-year period. Bivariate random intercept and slope modeling is applied to examine concurrently the cross-correlation between the two concurrent longitudinal trajectories from age 23 to 39. Parameter estimates indicate baseline level (at age 23) of employment to be negatively correlated with marijuana, suggesting marijuana-use is associated with lower workforce productivity at age 23. The longitudinal employment slope is positively correlated with employment intercept for both males and females, indicating that survey participants with higher levels of employment at age 23 are more likely to have a positive impact on employment trajectory over time. For males, however, the employment slope is also significantly correlated with marijuana intercept (r=-0.07), indicating marijuana-use in early adulthood may uniquely lower workforce productivity over age.
本研究分析了 7661 名参与 1979 年全国青年纵向调查（NLSY79）的个体的数据，以估算 17 年期间的就业和大麻使用轨迹。采用双变量随机截距和斜率模型，从 23 岁到 39 岁同时检查两个同时进行的纵向轨迹之间的交叉相关性。参数估计表明，就业的基线水平（23 岁时）与大麻呈负相关，表明大麻使用与 23 岁时的劳动力生产力降低有关。男性和女性的纵向就业斜率与就业截距呈正相关，表明 23 岁时就业水平较高的调查参与者更有可能随着时间的推移对就业轨迹产生积极影响。然而，对于男性，就业斜率也与大麻截距显著相关（r=-0.07），表明成年早期的大麻使用可能会独特地降低劳动力生产力随年龄增长的速度。
