Reports and studies on the costs of PROJECTS on construction projects have shown that they may not result in increased costs, such as a 2002 Harvard University Joint Center for Housing Studies paper, which indicates that the increase in costs cited by APA opponents is based on bids, not on final costs. According to the document, the final cost of a project due to construction costs would generally be higher than the cost of supply.  In addition, a 2004 report by the Director General of General Services in Contra Costa County, California, indicated that bids for five out of eight PROJECTS submitted to a PLA were lower than the cost estimate for architects/engineers.  In 2004, a report on the use of ALP in Iowa indicated that the use of PLA improves the efficiency and cost-effectiveness of construction projects. “Public LMPs for complex projects for which it is important to conclude the project in a timely manner have shown that they provide the service desired by contractors and project managers, which they use repeatedly.”  In a 2009 document, it was found that it was difficult to determine the impact of APAs on the cost of building schools, due to the distinction between schools built with GPs and those built without them. The report states that there is no statistically significant evidence of an increase in the cost of school construction.  One of the main arguments was the impact of TPCs on the cost of the project.  Those who oppose THE ACCORDS say that agreements impede competition for project offers and reduce the number of potential bidders, since non-union contractors are less likely to offer benefits because of the potential restrictions that a PLA may have.  Opponents of the agreements say that reduced competition leads to increased bids and costs for the project owner.  In addition, opponents argue that costs could also be increased as contractors would have higher costs under a PLA. For example, according to Max Lyons of the Employee Policy Foundation, the cost of a PLA project is increased by 7% because of the workload that contractors must give their employees the union salary and not the state-set remuneration.  Opponents also argued that there is evidence that PLA mandates increase costs by requiring non-union contractors to contribute to union performance plans and existing performance plans.  Proponents of the use of PLA argue that the final costs of projects are not increased where there is a LLP, compared to projects without such an agreement, as the agreements prevent cost overruns.
 In response, opponents of the agreements cite examples of projects for which a PLA has been completed and exceeded costs, including the Boston Big Dig Project, Seattle`s Safeco Field and San Francisco International Airport.  Three studies conducted in 2003, 2004 and 2006 by the Beacon Hill Institute on the use of PLA in school construction showed that the costs of projects in Massachusetts, Connecticut and New York that used PLA increased by 20%.    A 2009 study of Rider Levett Bucknall`s use of PLA to determine whether LPAs should be used in U.S. Department of Veterans Affairs construction projects showed that costs would increase if PPPs were used for construction projects in low-union sites. According to their analysis, the use of PLA in projects in areas such as Denver, Colorado, New Orleans, Louisiana and Orlando, Florida, where unions do not have a large presence, would result in a cost increase of 5 to 9%. In two cities, San Francisco and New York, where unions have a strong presence, the study predicted mixed results in terms of potential savings, ranging from a small increase in project costs to a small reduction in costs.  The first uses of Project Labor Agreements in the United States