The NYU researchers have some thoughts on why change remains so slow and incomplete. Part of the problem is sheer size of the industry, along with the lack of reliable data. Researchers found a total of 7,000 factories linked to export markets in Bangladesh. Previous estimates had put that figure much lower, at around 4,500. The discrepancies are largely because the depth of subcontracting was profound, with many registered factories relying on labor and goods from informal factories who don’t show up on official production rosters. These make up about half of all factories in the country, and one-third of the factories in Dhaka.

That’s particularly troubling because these indirect suppliers are harder to assess and control and are consistently involved in both major supply chains and garment factory tragedies. They aren’t registered with government entities or officially listed with brands, creating class of workers who are nearly invisible--and thus hard to protect via regulations and audits. Additionally, these shadow suppliers are often smaller and rely on more intense human labor so they can offer lower prices, undercutting official factories that are regulated and bearing the cost of paying workers minimum wage while keeping factories compliant with international and local standards. Further, it’s sometimes hard for suppliers to know whether their factories are subcontracting to these shadow suppliers.

In total, NYU’s report found about 5.1 million factory workers in Bangladesh, about 1 million more than estimated by the International Labour Organization, the organization responsible for much of the oversight and data gathering about global supply chains. In light of these adjusted figures, it’s clear that much of the progress touted by Bangladesh’s government—such as the 80 percent factory safety approval rate—is overstated, since around half of the factories involved in the creation of exports aren’t even on official rosters.

“The problems presented by an under-regulated and informal garment sector are much bigger than anyone has acknowledged up to this point,” the report’s authors write. But unfortunately,the vastness (and undercounting) of the supply chain isn’t the only problem.

In the wake of Rana Plaza, factory safety programs meant to improve fire and building protocols were agreed upon by politicians and several major brands such as Costco, Walmart, and Macy’s. But according to the NYU report, these agreements only cover 27 percent of factories and 45 percent of laborers who work for some of the largest and most advanced factories in the country. And for the most part, even the factories that fall under the purview of these programs haven’t completed the reforms necessary to make them safe. The holdup, the study finds, is a battle over who should pay for expensive electrical and structural upgrades—the factories or the brands that buy from them.