Card, Lemieux, and Riddell assert in their 2002 article "Unions and Wage Structure" that: They estimate that in 1981, the presence of unions reduced the variance in male wages by 6 percent. hundred in the United States. and 10 percent in Canada. Corresponding estimates in 1988 are 3 percent in the United States and 13 percent in Canada. Thus, they estimate that changing trends in unionization contributed to the increase in wage inequality in the United States in the 1980s, but had an opposite effect in Canada (20). a massive force in the United States as well as other countries, such as Canada and the United Kingdom, it is important to determine how this outcome is possible. Using theory developed around the topic of unionization, it may be prudent to use factors such as objective function, extent of bargaining, Rubenstein bargaining, all of which have an important impact on both the level of unionization in a company and on the salary implications. Additionally, union and non-union subject matter factors had a significant impact on the study results, indicating that a negative change in union participation contributed to an increase in wage inequality in the private sector, both unionized and non-unionized. unionized. After a lengthy review of the literature on the subject, Card and colleagues argue that "as this discussion [literature review] clearly shows, the impact of unions on the structure of relative wages depends on both the types of workers who tend to be unionized and how the relative wage impacts of unions vary across different groups of workers (Card, Lemieux, & Riddell, 7). This means that the demographics of union workers and the impact of union wages on these different groups are significant, including...... middle of article...... ng interest in men's unions over 30 years in the United States, however, this balance is quickly fading. The proportion of union wages relative to non-union wages instead follows a reduced form equilibrium model. Based on the above analysis of the work of Card, Lemieux and Riddell, the theory of unions studied in this course and the work of other renowned economists on the subject of unions. , it is evident that not only is the argument made by Card and his colleagues plausible, but it is probably a fact. From the bargaining power of unions and the application of the objective function to explain why the "male over 30" population is less interested in unions, to the application of models to determine if this change could indeed creating growing pay inequality across the sector. , it is clear that it is likely that such a theory can be successfully applied using models and theories..