Data Documentation for
"Trade Liberalization and the Theory of Endogenous Protection:
An Econometric Study of U.S. Import Policy," Journal of Political
Economy, February 1993, volume 101(1), pp. 138-160
by Daniel Trefler
September 29, 1994
The data are copyright. Users interested in the data must send a
written request to the author. The address is
Department of Economics
University of Toronto
150 St. George Street
Toronto, Ontario
Canada M5S 1A1
The data appear in two accompanying files, N.DAT and M.DAT .
N.DAT contains all the variables used in the NTB equation except
imports. M.DAT contains all the variables used in the import
equation except NTBs.
The following SAS UNIX code was used to write the files N.DAT and
M.DAT and read them back into a SAS file called MERGE.
*---- N.DAT: write data for the NTB equation --------------;
*Everything after "=" is a character string. Where ever
&varn appears, replace it with this character string;
%LET VARN = NTB_N SCRCONC BCRCONC SCRCOMP BCRCOMP MEPS KSTOCK
OCCUP5 OCCUP4 OCCUP2 OCCUP1 UNEMPLOY UNION NE GEOG2
TENURE X M80 VS79_83;
DATA ONE; SET ZERO;
FILE 'N.DAT';
PUT (&VARN) (19*11.7) " " IOCODE " " SIC4;
*---- M.DAT: write data for the gross imports equation ---;
*Everything after "=" is a character string. Where ever
&varm appears, replace it with this character string;
%LET VARM = M K_SERV INV ENGSCI WHITECOL SKILL SEMSKILL UNSKILL
CROPLAND PASTURE FOREST COAL PETRO MINERALS;
DATA ONE; SET zero;
FILE 'M.DAT';
PUT (&VARM) (14*11.7) " " IOCODE " " SIC4;
*---- MERGE: read the files back into SAS ------;
DATA TWO;
INFILE 'N.DAT';
INPUT &VARN IOCODE SIC4;
DATA THREE;
INFILE 'M.DAT';
INPUT &VARM IOCODE SIC4;
DATA MERGE;
MERGE TWO THREE;
BY IOCODE;
For those not familiar with SAS, each data file contains columns
separated by spaces and the variable order is the same as that in
the respective "put" statements above.
The following defines the variables and provides some statistics
to verify that the data have been read properly by the user.
Notes: 1. For the NTB equation, "skilled" is omitted since it is
1 minus the sum of the other 4 occupation variables.
2. Delta(import penetration) equals M - M80.
3. The industry code is IOCODE and is a 6-digit code from
the Bureau of Economic Analysis Input-Output
classification. SIC4 is the numerically smallest SIC
code that maps into IOCODE. See Appendix B of "Input-
Output Accounts of the U.S. Economy, 1983" in "Survey
of Current Business" 69 (Feb. 1989).
Variable N Mean Std Dev
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NTB equation
NTB_N 322 0.1105137 0.2387031 NTBs
SCRCONC 322 0.3781198 0.1899786 Seller concentration
BCRCONC 322 0.3754561 0.0703089 Buyer concentration
SCRCOMP 322 0.2700320 0.3548055 Seller number of firms
BCRCOMP 322 0.6670407 1.3184600 Buyer number of firms
MEPS 322 0.0302950 0.0597414 Scale
KSTOCK 322 0.3454289 0.2208742 Capital Stock
OCCUP5 322 0.0393972 0.0393853 Engineers, scientists
OCCUP4 322 0.2833637 0.0935765 White-collar
OCCUP2 322 0.3941035 0.1175837 Semiskilled
OCCUP1 322 0.0835156 0.0649416 Unskilled
UNEMPLOY 322 0.1211361 0.0587925 Unemployment
UNION 322 0.3457042 0.1291685 Union
NE 322 0.0490435 0.0878578 Employment size
GEOG2 322 0.6973935 0.1547467 Geographic conc.
TENURE 322 5.3801242 1.5672990 tenure
X 322 0.0906389 0.1238969 exports
M80 322 0.0829694 0.1263472 import penet., 1980
VS79_83 322 -0.1335873 0.2252051 industry growth
IOCODE 322 356630.17 160773.36 industry code
SIC4 322 3068.04 605.5315256 see note above
Import Equation
M 322 0.1076952 0.1517962 Import penetration
K_SERV 322 0.1108321 0.0331315 Physical capital
INV 322 0.0322772 0.0149108 Inventories
ENGSCI 322 0.0305586 0.0206737 Engineers, scientists
WHITECOL 322 0.1568722 0.0406919 White-collar
SKILL 322 0.1012067 0.0407723 Skilled
SEMSKILL 322 0.1165377 0.0395616 Semi-skilled
UNSKILL 322 0.0383608 0.0287589 Unskilled
CROPLAND 322 0.0235892 0.0644692 Cropland
PASTURE 322 0.0074905 0.0257857 Pasture
FOREST 322 0.000314535 0.0013469 Forest
COAL 322 0.0021271 0.0021443 Coal
PETRO 322 0.0321484 0.0462959 Petroleum
MINERALS 322 0.000995599 0.0023531 Minerals
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