1
Predicted Probability of PTA Formation
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
BITs with Developed Countries
Pr
obab
ili
ty
Figure 2
2
Table 1
Equations (1) and (2) by Rare Events Logistic Regression
DV: PTA
(1)
(2)
(3)
BIT-Dyad
0.318
0.430**
1.938***
(0.280)
(0.183)
(0.224)
BITs-SUM
-0.027
0.071*
(0.044)
(0.043)
BITs-SUM-Square
-0.006***
(0.002)
BIT-Dyad*
BITs-SUM
-0.199***
(0.029)
BIT-Dyad* BITs-SUM-Square
.004***
.001
TRADE
0.104
0.115
0.115
(0.241)
(0.254)
(0.234)
DISTANCE
-0.267***
-0.268***
-0.293***
(0.066)
(0.067)
(0.071)
SKILL
0.005
0.004
0.004
(0.004)
(0.004)
(0.004)
INCOME
-0.000***
-0.000***
-0.000***
(0.000)
(0.000)
(0.000)
ALLIANCE
0.749
0.760
0.828*
(0.531)
(0.505)
(0.441)
WTO
0.591
0.661
0.586
(0.636)
(0.663)
(0.648)
GDP
0.038
0.039
0.048
(0.061)
(0.060)
(0.057)
POLITY
-0.038
-0.034
-0.027
(0.051)
(0.052)
(0.051)
POPULATION
0.325*
0.342*
0.367*
(0.193)
(0.193)
(0.201)
AFRICA
-2.063*
-2.175*
-2.065*
(1.174)
(1.204)
(1.213)
APAC
-0.612
-0.654
-0.599
(0.985)
(0.955)
(0.956)
LAC
-0.193
-0.315
-0.201
(0.853)
(0.805)
(0.774)
Constant
-4.164
-4.267
-4.746
(3.689)
(3.650)
(3.817)
Observations
127578
127578
127578
Pseudo R^2
0.3382
0.3389
0.3573
Robust standard errors in parentheses
* significant at 10%; ** significant at 5%; *** significant at 1%
3
Table 2
Influence of BITs on Predicted Probability of PTA Formation
BIT
Regime
Predicted Probabil-
ity of Dyad Form-
ing a BIT
No Dyadic BIT
0.10
Dyadic BIT, but
no other BITs
0.44
Dyadic BIT and 7 other BITs
0.21
Estimates based on Table 1, Column (3), with all other variables
held at their means
Table 3
Predicted Probability of PTA Formation with and without a BIT
for Selected Countries
Probability with
Dyadic BIT
Probability Without
Dyadic BIT
BITS as of
2004
Colombia
0.56746
0.15789
0
Chad
0.15742
0.05005
3
Thailand
0.24322
0.17465
9
Bangladesh 0.2113
0.26954
12
Estimates based on Table 1, Column (3). All variables held at 2004 levels for all
country-specific variables and 2004 averages across dyads for dyadic variables
4
Table 4
Robustness Checks
(4)
(5)
(6)
BIT-Dyad 2.018***
1.461***
1.845***
(0.221)
(0.420)
(0.236)
BITs-SUM 0.083*
0.022
0.065
(0.043)
(0.065)
(0.043)
BITs-SUM-Square -0.003**
-0.002*
-0.004***
(0.001)
(0.001)
(0.001)
BIT-Dyad* BITs-SUM
-0.195***
-0.149***
-0.178***
(0.030)
(0.049)
(0.029)
DISTANCE -0.277***
-0.194**
-0.342***
(0.069)
(0.077)
(0.069)
INCOME -0.000***
-0.000**
-0.000***
(0.000)
(0.000)
(0.000)
ALLIANCE 0.911
0.476
0.654*
(0.585)
(0.659)
(0.382)
POPULATION 0.362*
0.459**
0.343*
(0.189)
(0.229)
(0.193)
AFRICA -1.869
-2.290*
-1.601
(1.195)
(1.225)
(1.161)
APAC -0.539
-2.569***
-0.239
(0.990)
(0.840)
(0.927)
LAC -0.064
-0.564
0.223
(0.877)
(0.840)
(0.772)
(0.756)
(2.151)
(0.901)
TRADE
0.091**
0.137
(0.040)
(0.244)
SKILL
-0.010
0.004
(0.006)
(0.003)
WTO
1.265
0.715
(0.861)
(0.567)
GDP
0.079**
0.065
(0.036)
(0.050)
POLITY
-0.000
-0.009
(0.044)
(0.040)
PTA-SUM
1.058***
(0.095)
PTA-SUM-Square
-0.059***
(0.006)
Constant -4.166
-11.398**
-4.439
(3.360)
(4.768)
(3.754)
Observations 121878
120845
116410
Pseudo R^2
0.3483
0.3122
0.4370
Robust standard errors in parentheses
* significant at 10%; ** significant at 5%; *** significant at 1%
5
Appendix A
Summary Statistics
Variable
Obs
Mean
Std.
Dev.
Min Max
PTA
130548
0.009435
0.096675
0
1
BIT-Dyad
130548
0.069308
0.253978
0
1
BITs-SUM
130548
1.59408
3.110406
0
19
BITs-SUM-Square 130548 14.86166
46.06932
0
361
BIT-Dyad* BITs-SUM
130548 0.531115
2.369902
0
19
TRADE
130548
0.098051
0.584308
-2.43435
57.632
DISTANCE
130548
7.508011
3.920736
0.059617
19.6295
SKILL
130548
24.34388
15.57239
-40.6847
97.74065
INCOME
130548
14435.77
7958.769
-13883.9
41789.6
ALLIANCE
130548
0.018698
0.135457
0
1
WTO
130548
0.455892
0.498053
0
1
GDP
130548
1.584551
2.453486
-12.8111
23.07724
POLITY
130548
-2.04993
6.568754
-27.6909
25.84851
POPULATION
130548
15.597
1.67467
11.00709
20.98563
AFRICA
130548
0.363636
0.481048
0
1
APAC
130548
0.166667
0.372679
0
1
LAC
130548
0.189394
0.391823
0
1