External NTM Datasources
Trade analysis has applied many different sources of NTM data that considerably influence the results and their interpretation. NTMs are defined by four main elements: the measure, the country imposing the measure and the country affected by the measure and the product affected. The level of details about the measures considerably differs. The information provided ranges from binary variables that indicate whether a measure is in place or not, ordinal variables indicating a ranking along a chosen dimension or numerical variables reflecting quantitative attributes of an NTM.
Information about the time, i.e. the publication of the legal text that describe the measures or their implementation, may also be provided. Usually, the NTM information provides a snap-shot of the respective year of data collection.
The most direct source of NTM data are regulatory inventories in which national legislation is meticulously reviewed by coding which measures are specified in the legal body of a country and thus imposed on products from partner countries. Information on NTMs is also provided in policy reviews of a country’s trade policy. Such reviews usually do not systematically apply codes for measures and products. Notifications to the WTO are another source of NTM data. They are about changes of laws and regulations as well as their administration. Usually, the information is provided in text format but codes for measures and to a limited extent also codes for products are provided. Surveys and complaint portals gather information about the perceptions about the impact of NTMs from a business point of view. Such information is complementary to the inventory or listings of regulations or changes of regulations. Note that information on the enforcement of NTMs is generally lacking. However, especially for SPS and TBT measures, import refusals point out compliance or rather non-compliance.