Hard to find anything remotely unbiased, or that does even a passable job at trying to remove confounding factors between the rate of unionization and commonly cited benefits like the rise in worker safety (which is overwhelmingly driven by rising standard of living). Got any economically literate reading recommendations?
If your argument is “consider this anecdote”, and you can’t imagine historical analysis of economic questions other than through non-quantitative hand-selected case studies, you’re falling into the same trap.