The causal link between victimization and violence later in life is largely accepted but has been understudied for victimized adolescents. In this work we use the Add Health dataset, the largest nationally representative longitudinal survey of adolescents, to estimate the relationship between victimization and future offending in this population. To accomplish this, we derive a new doubly robust estimator for the average treatment effect on the treated (ATT) when the treatment and outcome are not always observed. We then find that the offending rate among victimized individuals would have been 3.86 percentage points lower if none of them had been victimized (95% CI: [0.28, 7.45]). This contributes positive evidence of a causal effect of victimization on future offending among adolescents. We further present statistical evidence of heterogeneous effects by age, under which the ATT decreases according to the age at which victimization is experienced. We then devise a novel risk-ratio-based sensitivity analysis and conclude that our results are robust to modest unmeasured confounding. Finally, we show that the found effect is mainly driven by non-violent offending.

翻译：受害者经历与后期暴力行为之间的因果关系已被广泛接受，但针对受欺凌青少年的相关研究仍不充分。本研究采用美国最大规模全国代表性青少年纵向调查数据"Add Health"，评估青少年遭受欺凌对其未来犯罪倾向的影响。为完成该分析，我们提出了一个新型双重稳健估计量，用于处理治疗变量与结果变量均存在缺失情况时受试者平均处理效应（ATT）的估计。研究发现，若所有受欺凌个体均未遭受欺凌，其犯罪率将降低3.86个百分点（95%置信区间：[0.28, 7.45]）。这一结果提供了青少年阶段欺凌经历对后续犯罪行为存在因果效应的实证证据。进一步分析表明，处理效应存在年龄异质性——随着遭受欺凌年龄的增加，ATT呈现递减趋势。我们创新性地提出基于风险比的敏感性分析方法，证实主要结论对中等程度的未测量混杂因素具有稳健性。最终发现，观测到的效应主要由非暴力犯罪行为驱动。