Justice for Janitors campaign was included in a recent study concluded by the Future of Work that shows the importance of increasing union density in the private sector in order to strengthen worker voices at their workplaces and vis-a-vis their employer.
The study suggests varying other ways in which workers can gain, including through raising wages and working standards via legislation and pressuring employers through community. Unionization features predominantly in the report.
The full report can be viewed here, and below is the excerpt covering the Justice fo Janitor campaign (page 36 in the study).