Employment relations scholars argue that industrial relations institutions reduce low pay among the workforce, while the insider-outsider literature claims that unions contribute to increase the low-pay risk among non-union members. This article tests these expectations by distinguishing, respectively, between the individual effect of being a union member or covered by collective agreements and the sectoral effect of strong trade unions or encompassing collective agreements. Findings from multilevel logistic regression analyses of the German Socio-Economic Panel reveal that unions and bargaining coverage have distinct effects at individual and sectoral level. The analysis of their cross-level interactions provides partial support to both the insider-outsider approach, since non-union members are more exposed to the risk of low pay in highly unionized sectors, and to the power resource perspectives, since the probability of being in low pay in sectors with encompassing collective agreements decreases also for those workers who are not covered by them.

雇佣关系学者认为，劳资关系机构降低了劳动力中的低工资，而内部-外部文献声称工会有助于增加非工会成员的低工资风险。本文通过分别区分成为工会成员或集体协议所涵盖的个人影响和部门影响来测试这些期望强大的工会或包含集体协议。德国社会经济小组的多级逻辑回归分析结果表明，工会和谈判覆盖率在个人和部门层面具有不同的影响。对他们的跨级别互动的分析为内部-外部方法提供了部分支持，因为非工会成员更容易受到高度工会化部门的低薪风险和权力资源的影响，因为在包含集体协议的部门的低工资中，那些未被这些协议覆盖的工人也减少了。