The only reliable source (we know of) for non-union vs. union employment data in the state's construction industry is out with the 2018 numbers. Unionstats.com posted the 2018 figures on Feb. 2.
As a percentage of the construction workforce, merit shop workers increased in 2018 to 84.9%, up from 83.2%. Conversely, construction union membership in Massachusetts was 15.1%, down from 16.8%.
The figures demonstrate that construction workers, by a clear and enduring supermajority, prefer to work for merit shops and outside the union system. Construction workers have a free choice to work for merit shops or join a labor union, and 4 out of 5 choose non-union.
Please, remember that the next time you hear organized labor represents the workers. Actually, the great majority of construction employees make a different choice.