progressive rule book – one that includes enforceable agreements against child labor and workplace discrimination, measures to punish illegal logging and trade in protected species, and protections against consumer fraud – would mark a substantial step forward in the progressive policy agenda on the global stage." In May 2015, U.S. congressman Sander Levin argued that it is difficult to enforce trade deals, as he questioned Vietnam's willingness to meet the labour standards of TPP. A report by U.S. Senator Elizabeth Warren said that there was a huge gap between the labor standards of past US free trade agreements and the actual enforcement of those provisions. However, PIIE analysts note that research shows that the presence of "sticks" (a possible suspension of trade benefits) and "carrots" (technical assistance) in trade deals increase the likelihood that labor obligations in trade deals have a positive effect; there are both sticks and carrots present in TPP. Regulatory cooperation Even though the TPP had not been passed, the agreement had already introduced forms of regulatory cooperation for agriculture beyond that found in the WTO. This means that regulators in different TPP signatories have been engaging with each other and building trust. Chad P. Bown, senior fellow at the Peterson Institute for International Economics, argues that this regulatory cooperation meant that the US poultry industry was not as hard-hit by the 2015 bird flu outbreak, as regulators in TPP countries cooperated and continued to accept US exports of poultry. Economic impact The U.S. International Trade Commission, the Peterson Institute for International Economics, the World Bank and the Office of the Chief Economist at Global Affairs Canada found that the final agreement would, if ratified, lead to net positive economic outcomes for all signatories. Effects on economic equality In 2013, Nobel Memorial prize-winning economist Joseph Stiglitz warned that, based on leaked drafts of the TPP, it "serves the interests of the wealthiest." Organised labour in the U.S. argued, during the negotiations, that the trade deal would largely benefit corporations at the expense of workers in the manufacturing and service industries. The Economic Policy Institute and the Center for Economic and Policy Research have argued that the TPP could result in job losses and declining wages in the U.S. Economists Peter A. Petri and Michael G. Plummer challenge the view that TPP will primarily benefit the wealthy. Their analysis finds that "the gains from TPP appear to be