Project Labor Agreements (PLAs) are comprehensive pre-hire collective bargaining agreements that establish uniform terms and conditions of employment for all craft workers—union and non-union—on a specific construction project. In the United States, the use of PLAs on publicly funded projects is a contentious policy issue, creating a sharp divide between labor advocates and non-union contractor associations. The debate intensified with the issuance of Executive Order 14063, which mandates PLAs on large-scale federal construction projects valued at $35 million or more, aiming to promote economy and efficiency in federal procurement.1
The central problem this paper addresses is the conflicting evidence and polarized claims surrounding the impacts of PLAs. Proponents argue that these agreements ensure labor stability, prevent disruptions, and guarantee access to a highly skilled workforce, leading to on-time, on-budget project completion and superior workforce outcomes.1 Conversely, opponents contend that PLAs inflate project costs, restrict competition by discouraging non-union contractors from bidding, and unfairly favor unionized labor.1 This tension is evident in recent policy actions, such as the Department of Defense’s 2025 class deviation, which effectively nullified the PLA mandate for its large-scale projects, citing its own contracting authority.2 This paper seeks to move beyond the political rhetoric by systematically analyzing the available evidence. The objective is to synthesize empirical findings on the dual performance of PLAs, evaluating their effects on key metrics of economic efficiency (cost, competition, timeliness) and workforce welfare (apprenticeship, local hiring, diversity, and safety).
The legal and policy landscape for PLAs in the United States is fragmented and contested. The foundation for their use on public projects was established in the 1993 Supreme Court case Building & Constr. Trades Council v. Ass’d Builders & Contractors of Mass./R.I., Inc. (the “Boston Harbor” case). The Court ruled unanimously that when a public entity mandates a PLA for a project it funds, it acts as a “market participant” rather than a regulator, and thus its actions are not preempted by the National Labor Relations Act.3 However, this ruling did not address competitive bidding laws, leaving an avenue for state-level legal challenges. Consequently, a stark jurisdictional divide has emerged: states like California, New York, Illinois, and Washington have statutes or executive orders that encourage or authorize PLAs, while 25 other states have enacted laws banning government-mandated PLAs on public projects.3
The debate over the economic efficiency of PLAs is characterized by contradictory empirical findings. Regarding project costs, the Congressional Budget Office (CBO) concluded it lacks sufficient data to determine whether PLAs result in significant costs or savings for the federal government.4 This ambiguity is reflected in competing studies. For instance, a 2020 analysis of Connecticut school construction projects concluded that PLA mandates increased costs by 19.8%.5 This aligns with claims from opponents that PLAs could raise costs by up to 20% and exclude the majority of the construction workforce.1,6 In sharp contrast, a comprehensive 2025 study of 773 projects in Illinois found that PLAs had no statistically significant effect on construction costs.8
Similarly, the impact on bidder competition is disputed. A 2019 study in Washington state found that PLAs reduced the average number of bidders by 18.26%.7 A survey by the Associated Builders and Contractors (ABC) reported that 99% of its members were less likely to bid on a project with a PLA mandate.6 However, the 2025 Illinois study contradicted this narrative, finding that PLAs were associated with a 14% increase in bid competition.8
While the economic evidence is contested, the literature presents more consistent findings regarding workforce welfare. PLAs are frequently linked to the expansion of apprenticeship programs and the promotion of a diverse workforce. A 2024 study of Port of Seattle projects found that those with PLAs were 26 percentage points more likely to meet goals for women apprentices and had a higher share of apprentice hours worked by people of color.9 In Minneapolis, the PLA for the U.S. Bank Stadium was instrumental in exceeding hiring goals, with minority workers performing 36% of work hours (vs. a 32% goal) and women performing 9% (vs. a 6% goal).10 PLAs have also been used to enforce local hiring provisions. In California, projects for the Port of Oakland and Los Angeles Community College District successfully met or exceeded local hiring targets.11 However, achieving these goals is not always guaranteed; a case study of the Washington, D.C., Nationals Stadium PLA found it exceeded apprentice residency goals but fell short on journey worker residency targets.12 A further challenge is apprentice retention, with one California study noting lower graduation rates for Latinx, Black, and female apprentices despite their high representation in incoming cohorts, pointing to systemic issues beyond initial recruitment.13
This paper employs a systematic literature review and synthesis of existing research to analyze the effects of Project Labor Agreements in the United States public construction sector. The methodology is qualitative, focusing on the aggregation and interpretation of findings from a diverse body of sources, including peer-reviewed studies, government reports, policy analyses, and case studies. The geographic scope is national, encompassing federal PLA policy as well as state-level frameworks and project outcomes in key jurisdictions with significant PLA activity, such as California, New York, Illinois, and Washington.
The analysis is structured around two primary frameworks:
This dimension is evaluated through a multi-metric approach. The primary metrics include: (1) Total project costs, examining evidence of cost inflation or savings; (2) Bidder competition, assessing the impact on the number and diversity of contractors bidding on projects; (3) On-time and on-budget completion, considering claims of improved project management and stability; and (4) Long-term value and quality, a conceptual metric reflecting the whole-life cost of the asset.
This framework assesses the social and labor-focused outcomes of PLAs. Key metrics include: (1) Wage and benefit standards, which are standardized under PLAs; (2) Apprenticeship and skill development, measured by the utilization rates of registered apprenticeship programs; (3) Local and targeted hiring, evaluating the success of provisions aimed at employing workers from specific communities or demographic groups; and (4) Workplace safety and health, drawing on established links between unionization and safety outcomes.
By synthesizing the divergent findings within these frameworks, this study aims to provide a nuanced understanding of the trade-offs and policy implications associated with PLA mandates.
The analysis of the collected research reveals a stark dichotomy: evidence concerning the economic efficiency of PLAs is deeply contested and often contradictory, whereas findings related to workforce welfare and development are more consistent and largely positive.
The central debate over PLAs revolves around their effect on project costs and market competition, where the evidence is inconclusive. Opponents frequently point to studies like the Beacon Hill Institute’s analysis of Connecticut school construction, which concluded that PLA mandates added 19.8% to project costs.5 This figure is often cited in political discourse, alongside claims that PLAs deter the vast majority of the construction industry from bidding on federal projects.1 A survey of non-union contractors reinforces this perspective, with 99% of respondents stating they are less likely to bid on a project with a PLA requirement, and 97% believing such a project would be more expensive.6 Further, a study of projects in Washington state provided empirical support for reduced competition, finding that PLAs decreased the number of bidders by 18.26%.7
However, this narrative is directly challenged by other significant research. A comprehensive 2025 analysis of 773 public projects in Illinois conducted by the Illinois Economic Policy Institute found that PLAs had no statistically significant impact on final project costs.8 More strikingly, the same study concluded that PLAs were associated with an average 14% increase in bidder competition.8 This finding suggests that in certain markets, PLAs may not be the barrier to competition that opponents claim. The profound disagreement between the Washington and Illinois studies, coupled with the CBO’s official position of insufficient data,4 indicates that the economic impact of PLAs is not uniform but is likely contingent on regional market conditions, the specific terms of the agreement, and the methodology of the study itself.
In contrast to the economic debate, the role of PLAs in advancing workforce welfare objectives is supported by more consistent evidence. PLAs are shown to be effective mechanisms for implementing targeted social policies through public construction investment. A key area of success is in apprenticeship and workforce diversity. For example, an analysis of Port of Seattle projects revealed that those governed by a PLA were 26 percentage points more likely to meet goals for women apprentices.9 Similarly, the Illinois study found that PLAs were associated with a 1 to 2 percentage point increase in the market share for businesses owned by women, people of color, and veterans.8
PLAs with explicit community workforce agreement (CWA) provisions have demonstrated measurable success in local and targeted hiring. The PLA for U.S. Bank Stadium in Minneapolis, which included specific equity goals, resulted in minority workers performing 36% of work hours and women performing 9%, exceeding both targets.10 In California, PLAs for the Port of Oakland and Los Angeles public agencies successfully met and surpassed local hiring goals of 50% and 30%, respectively.11 These outcomes show that PLAs can be powerful tools for ensuring that the economic benefits of public investment are directed toward local and historically disadvantaged communities.
Nonetheless, challenges remain. The case of the D.C. Nationals Stadium showed mixed results, where goals for local apprentice hours were exceeded but targets for local journey worker hours were not met.12 This highlights the complexity of implementation. Furthermore, a 2020 analysis of California’s apprenticeship system revealed that while recruitment of diverse apprentices was high, Latinx, Black, and female apprentices experienced lower graduation rates than their white and Asian male counterparts.13 This indicates that while PLAs can create pathways into the trades, broader systemic support is needed to ensure long-term retention and career progression.
The findings of this review underscore a fundamental tension in the evaluation of Project Labor Agreements. The discourse is dominated by a debate over economic efficiency, where the evidence remains polarized and inconclusive. Simultaneously, a growing body of research provides more consistent, positive evidence of PLAs’ effectiveness as a policy tool for achieving workforce welfare and development goals. The decision to use a PLA, therefore, represents a critical policy choice about prioritizing objectives.
The contradictory evidence on costs and competition suggests that there is no universal economic outcome associated with PLAs. The disparity between findings in Washington,7 Connecticut,5 and Illinois8 indicates that local market dynamics, the density of union labor, the specific provisions within the PLA, and the research methodology employed are all critical variables. The perception among non-union contractors that PLAs are exclusionary is a significant factor,6 but its actual impact on bidding behavior appears to vary by region. It is plausible that in markets with strong union presence and established labor-management relationships, PLAs can enhance coordination and predictability without negatively impacting competition, as suggested by the Illinois findings.8
In contrast, the value proposition of PLAs for workforce welfare is much clearer. The consistent success in boosting apprenticeship utilization and meeting local and diverse hiring goals across different jurisdictions—from Seattle9 to Minneapolis10 to Los Angeles11—demonstrates that PLAs are a reliable instrument for executing social policy objectives. These are not merely ancillary benefits; for many public agencies, ensuring that large-scale investments create equitable opportunities for local residents and diverse populations is a primary goal. PLAs provide a contractual framework to enforce these goals, which may otherwise be difficult to achieve through standard procurement processes.
However, the research also highlights important limitations. The findings on apprentice retention in California suggest that getting diverse workers onto a job site is only the first step.13 Without a corresponding focus on creating an inclusive workplace culture and providing support for program completion, the full promise of equity may not be realized. Furthermore, the political and legal opposition to PLAs, evidenced by bans in 25 states3 and the Department of Defense’s policy deviation,2 remains a significant barrier to their wider adoption. This opposition, rooted in the economic efficiency argument, often overlooks the more substantiated workforce benefits.
This paper has synthesized the divergent body of evidence on the impact of Project Labor Agreements on public works projects in the United States. The analysis confirms that the debate is characterized by a deep schism. On one hand, the effect of PLAs on economic efficiency metrics like project cost and bidder competition is inconclusive, with credible studies and data supporting opposing conclusions. The federal government’s own assessment, via the CBO, acknowledges a lack of definitive information. On the other hand, the evidence is substantially more consistent and positive regarding the role of PLAs in advancing workforce welfare goals, including enhancing apprenticeship training, achieving local and diverse hiring targets, and ensuring uniform wage and safety standards.
The primary implication for policymakers and public agencies is that the decision to mandate a PLA is not a simple economic calculation but a strategic policy choice. It requires weighing uncertain and contested effects on project budgets against more certain and demonstrable benefits for workforce development and community equity. The effectiveness of a PLA appears to be highly context-dependent, influenced by local market conditions and the specific goals embedded within the agreement.
Future research should move toward resolving the empirical contradictions. Longitudinal studies that track the full lifecycle costs of PLA and non-PLA projects would provide a more complete picture of long-term value. Comparative analyses that isolate the impact of specific PLA provisions—such as local hiring clauses versus standardized safety protocols—could help identify which components drive costs or benefits. Finally, further investigation is needed to understand why bidder competition appears to react so differently to PLAs in different regional markets, which could help in designing more effective and less contentious agreements.
