Chor (2019), Waugh (2019) and Bown, Jung and Lu (2019a). We find that this assumption
is justified because the value of U.S. exports that we classify as being covered by retaliatory
tariffs lines up well with those calculated by other researchers as well as those announced by
U.S. trade partners, as reported in Table A2.
Our measures of exposure to the various rounds of tariffs imposed by the U.S. and its
trading partners also require data on the value of overall imports, exports and shipments.
We collect data on the dollar value of U.S. imports and exports from the United States
International Trade Commission. For annual levels of industry shipments, we use the most
recent year of the Annual Survey of Manufactures (ASM), 2016. Data on the input usage
of each industry are drawn from the BEA’s input-output tables for 2012, the most recent
vintage available.
Lastly, we draw monthly values of the dependent variables for our analysis—industry
output, employment, and producer prices—from three sources. Our measures of monthly
industry output come from the Federal Reserve’s G.17 Release on Industrial Production
and Capacity Utilization. For monthly estimates of employment at the industry-level, we
utilize data from the Current Employment Statistics (CES) program of the Bureau of Labor
Statistics. Finally, we use the producer price index, also from the Bureau of Labor Statistics,
to measure monthly changes in prices across industries.
2.4 Level of Aggregation
We conduct the analysis at the level of four-digit NAICS industries, which is the most de-
tailed level at which comprehensive data for industrial production, producer prices, and
employment are available at a consistent level of aggregation, with several exceptions. First,
we separate aluminum manufacturing (NAICS 3313) into three sub-industries to reflect an
important distinction within the industry that is impossible to ignore given the set of tariffs
we study. Primary aluminum production (NAICS 331313) consists of establishments largely
making aluminum from raw materials like alumina and bauxite. The remaining components
of NAICS 3313 (NAICS 331314: Secondary Smelting and Alloying of Aluminum, NAICS
331315: Aluminum Sheet, Plate, and Foil Manufacturing, and NAICS 331318: Other Alu-
minum Rolling, Drawing, and Extruding) manufacture aluminum from scrap, dross, or other
existing aluminum. As is clear from this definition, primary aluminum manufacturers would
be protected by the U.S. tariffs on aluminum, while the same tariffs would apply to both the
output and inputs of the second group of producers. Therefore, we split NAICS 3313 into
primary aluminum production (NAICS 331313), secondary aluminum production (NAICS
331314), and the combination of NAICS 331315 and 331318, consistent with the industry
splits used in the BEA input-output tables.
Second, there are exceptions to the use of the four-digit NAICS classification due to data
limitations. In particular, there are some industries (NAICS 315: Apparel Manufacturing,
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