Production assumption – indicators created via input-output techniques are limited by the degree of industry disaggregation provided by the tables. As shown above, the national input-output tables used by the OECD are based on a harmonized set of 37 industries. Any given indicator, therefore, assumes that all consumers of a given industry’s output purchase exactly the same shares of products produced by all of the firms allocated to that industry. This boils down in practice (but is not the same thing) to assuming that there exists only one single production technique for all of the firms and all of the products in the industry grouping. We know that this is not true and that different firms, even those producing the same products, will have different production techniques and technical coefficients, and we also know that different firms produce different products and that these products will be destined for different types of consumers and markets. A chief concern in this respect is the evidence that points to exports having very different coefficients to goods and services produced for domestic markets, particularly when the exports (typically intermediate) are produced by foreign-owned affiliates in a global value chain. Because exporting firms are generally more integrated into value-added chains, they will typically have higher foreign content ratios, particularly when they are foreign owned. As such, the estimates provided in this version should be considered as prudent. Generally, they will point to lower shares of foreign content than might be recorded if more detailed input-output tables were available with consequences for all other indicators presented. One important innovation in the indicators presented here is to use specially constructed input-output tables