Conclusion
The aim of this paper was to contribute to the advancement of the debate on employee voice and performance by analyzing how collective employee voice mechanisms (i.e., union voice and team voice) affect organizational productivity and how these relationships vary when voice mechanisms are adopted in combination with other HRM practices. Despite the debate on union decline and the (supposed) superiority of direct voice, union voice was found to be positively related to labor productivity, whereas team voice did not show any significant relationship with organizational performance. Interestingly, collective voice mechanisms were also found to moderate the relationship between some high-performance HRM practices and productivity, such as variable pay and training. Specifically, the positive relationship between variable pay and productivity is significant only at the high level of union voice, whereas the positive relationship of training is stronger when team voice is high and when union voice is low. Overall, these results confirm the need to adopt research frameworks that are able to integrate different theoretical perspectives when analyzing the role of employee voice in contemporary workplaces (Townsend & Wilkinson, 2014; Barry & Wilkinson, 2016; and Kaufman, 2015). Focusing only on direct (and individual) voice mechanisms means, at best, having a partial representation of the contribution thatemployee voice can make to organizational performance.