In our deeply unequal age, we’ve become accustomed to talking about concepts like income and wealth, affluence and poverty. Researchers at the OECD, the developed world’s official economic research agency, would like to toss another concept into the inequality mix: economic vulnerability. Why do we need to talk about vulnerability? Wealth and income stats alone, a new OECD study points out, often don’t tell us the whole story about who’s prospering and who’s not. One example: Households with decent incomes often don’t have much in the way of assets. In these asset-poor households, any serious disruption — a sudden job loss, a family breakdown, a disability — could bring economic disaster. How many households are living at the precipice of this disaster? The OECD’s new economic vulnerability study has an alarming answer. The study covers the United States and 27 other major developed nations.