Journal article: The health crisis has underscored the need for national accounts that can track the activity and financial situations of various groups of economic agents as quickly as possible. It also raises several questions about how real GDP aggregates quantities of heterogenous goods and services that meet very different needs whose relative priorities have been affected by the crisis, at least temporarily. We focus on two aspects of this question: the theoretical properties of aggregation by chaining at market prices for the market share of GDP and the joint problems of measurement and significance of the aggregate for its non-market components. Beyond the short-term shock, the crisis provides an opportunity to revisit some substantive issues regarding the interpretation of output and real growth indicators, issues that the post-crisis period should continue to fuel.