A union welder during a ribbon-cutting ceremony and demonstration at Solid Platforms Inc.’s new manufacturing facility, Friday, January 16, 2026, in Johnstown, Pa.
First study to measure PLA project duration finds 15% to 17% faster completion on public works
Public construction projects built under project labor agreements (PLAs) reach the finish line significantly faster than projects without them, according to a peer-reviewed study in ILR Review.
The study is the first to measure whether PLAs affect how long public construction takes. Researchers Larissa Petrucci, Matthew Hinkel and Grace Dunn analyzed 313 public works projects in Sacramento County, California, completed between 2019 and 2023. After controlling for project cost, project type and the awarding agency, they found that PLA projects were completed 15% to 17% faster than comparable non-PLA projects.
The duration advantage held at a high level of statistical confidence. The authors also found that PLA projects were 43% more likely to be finished within the following year than non-PLA projects.
READ MORE: Do PLAs increase costs? Here is what the research shows
The researchers point to the structure of PLAs to explain the gap. By securing access to skilled tradespeople through union hiring halls and aligning work schedules across the crafts, the agreements keep projects moving. Provisions that bar strikes, work stoppages and lockouts, paired with built-in dispute resolution, remove common sources of delay before they start.
Timing mattered even more during the years studied. Most of the projects were built during the coronavirus pandemic, when contractors across the industry struggled to find workers. The authors suggest PLAs may be especially valuable during labor shortages, because union hiring halls give contractors a reliable pipeline of qualified workers exactly when they are hardest to find.
The findings add a new dimension to PLA research, which has focused mostly on construction costs and bid competition. Faster completion can also reduce costs by shortening labor time and limiting the expense of shutting down and restarting work, though the authors note their study does not measure cost directly.
READ MORE: Project labor agreements do not raise costs, research review finds
