The new OECD study tells us exactly how insignificant workers' voices are in the ESG (environmental, social and governance) metrics and ratings schemes. In Behind ESG Ratings—Unpacking Sustainability Metrics, the OECD reviewed more than 2,000 ESG metrics from eight major ESG rating products.

They found that two-thirds of metrics used to assess ESG performance are company inputs, that is, companies' self-reported data about their policies and activities. In the case of labour rights and human rights performance, more than 80% of ESG data is self-reported by companies. Even more concerning, the OECD did not find a single metric about social performance in supply chains—including labour rights—that was not self-reported.

What does this mean? Based on the OECD study, public buyers, investors, and consumers cannot rely on ESG scores and ratings to ensure their procurement, investment, or purchases do no harm to workers in supply chains. Over-reliance on input-based metrics from companies themselves creates the risk that the scoring is marred by conflict of interest. The lack of attention to the outcomes of the reported policies and activities could also "incentivise 'tick-boxing' approaches over actual risk prevention and mitigation actions," warns the OECD. Independent sources such as civil society organisations and media are sidelined in these schemes, and workers in supply chains are silenced.

ESG ratings and scores are more likely to hide than reveal harm to workers in global supply chains. To the extent investors rely on such metrics to inform investments, policy makers to hold companies accountable, or public buyers to conduct procurement, they do so blind to workers in global supply chains.

In his recent essay, Mandatory Human Rights Due Diligence: An Opportunity for Workers or Big Business?, Electronics Watch Executive Director Björn Claeson warned that workers' voices were being drowned out by the overabundance of ESG data points. Without a concerted effort to engage trade unions, civil society organisations and workers themselves, those who are most at risk of rights abuse will be the least likely to be heard.

"A worker's direct report is but one of many thousands of data items. Its importance is diminished by the overabundance of other information points. Moreover, workers who are most at risk of rights abuse are the least likely to make their voices heard; their abuse is unlikely to trigger even a single data point," he argues.

The OECD study is further evidence that any organisation seeking to protect the rights of workers in their global supply chains should eschew the misguided approach of ESG rating schemes. Instead, companies should build new relations with trade unions and civil society organisations that interact with workers. They should participate in processes where workers or their representatives have equal voice. Governments, investors, and public buyers should incentivise them to do so, or they run the risk that ESG scores and ratings will continue to conceal harm done to workers in their supply chains.