The depth index is a simple additive index of 7 key statements that can be part of a PTA.
The 7 key statements are tariff reduction, intellectual property rights protection, government purchases, technical barriers to trade, services, investments and compe-tition. The scale of the index is 0 – 7. The depth measure used here was developed by Dür, Baccini, and Elsig (2014)
The depth of PTAs is heterogeneous. Some PTAs cover a large number of different issues, from trade in services to government purchases, whereas others are very narrow. Some PTAs include far-reaching statements, while others are relatively shallow.
For example, a PTA with a depth score of 0 is an agreement with no substantive statements in any of the 7 key statements. On the other extreme, a PTA with a depth score of 7 is more than an agreement with substantive statements in all 7 key statements.
Further details on the index are provided in Table 1
Note that the depth index is not available (N.A.) for all PTAs because the researchers did not find full texts for all agreements.