Appendix to
“Taking a Walk on the Supply Side:
The Determinants of Civilian Nuclear
Cooperation”
Matthew Fuhrmann
Journal of Conflict Resolution, Vol. 53, No. 2 (April 2009)
2
In this online appendix, I perform some additional sensitivity analysis to further
assess the robustness of my findings. In particular, I add additional control variables to
the model, exclude safety-related nuclear cooperation agreements (NCAs) from the
dependent variable, and exclude minor suppliers from the sample.
The models displayed in Table I add six control variables. These new control
variables are added to the model, one by one, in Models 1-6. The importing state’s
security environment could affect its demand for nuclear technology. To control for this,
I include a dummy variable that is coded 1 if the recipient state is involved in a rivalry in
year t-1 and 0 otherwise. To code this variable, I consult the Klein, Goertz, and Diehl
(2006) rivalry dataset. There are a number of additional economic variables that could
plausibly influence civilian nuclear assistance. I add a control variable measuring the
total amount of trade between the supplier and recipient countries based on data compiled
by Gleditsch (2002). I also control for the existing nuclear resources possessed by the
supplier and recipient states. Countries with greater nuclear-related capacity may be
more likely to provide nuclear assistance and states that have such capacity more be more
likely to demand atomic aid. I include variables measuring the supplier and importing
states’ nuclear resources in year t-1 using Jo and Gartzke’s (2007) nuclear production
data. The Jo and Gartzke (2007) index measures nuclear production capacity based on
seven measures including: domestic nuclear deposits; metallurgists; chemical engineers;
nuclear engineers; electronic/explosive specialists; nitric acid production capabilities; and
electricity production capabilities. To control for the importing state’s energy demand, I
include a variable measuring the ratio of the country’s energy production capacity to its
population. These data are obtained from the COW’s National Military Capabilities
3
dataset (Singer, Bremer, and Stuckey 1972). Finally, the price of oil might affect a
state’s demand for nuclear energy. To control for this, I include a variable measuring the
price of a barrel of oil measured in U.S. dollars in year t-1. Data on oil prices come from
the Historical Statistics of the United States (2006).
The models estimated in Table II exclude safety-related NCAs from the
dependent variable since these agreements are the least sensitive and in some respects are
qualitatively different from transfers of reactors or other nuclear equipment/materials.
This removes 685 NCAs and leaves a total of 1,785 non-safety related agreements from
the dependent variable. In Table III, minor-suppliers are excluded from the sample since
suppliers with relatively limited export potential like China, Pakistan, and South Africa
might behave differently than major suppliers like the United States. The suppliers
included in the sample for these models are: the United States, Canada, the United
Kingdom, France, Germany, Italy, and Russia.
The results show that these changes have very little effect on my core findings. In
virtually all of the models presented in Tables I, II, and III the five variables
operationalizing my argument have statistically significant effects in the expected
directions. There is one notable difference. In three models (Model 2, Table II; Model 6;
Table II; and Model 2, Table III), militarized conflict does not have a statistically
significant effect on nuclear assistance. But this variable is still significant in 9 of the 12
models presented here. There are no significant changes to the findings for the control
variables. This sensitivity analysis should generally inspire further confidence among
readers that my key findings are robust.
4
Table 1: Results with Additional Control Variables
Supplier’s Strategic
Interests
Alliance
Militarized Conflict
Shared Enemy
Superpower Enemy
Joint Democracy
Economic
Incentives
Supplier’s GDP
Recipient’s GDP
Distance
Nonproliferation
Nuclear Weapons
NPT
NSG
Contagion Effects
Regional NCAs
Additional Controls
Recipient Rivalry
(1)
(2)
(3)
(4)
(5)
(6)
0.866***
(0.093)
1.147***
(0.412)
0.915***
(0.090)
1.147***
(0.420)
0.869***
(0.090)
1.118***
(0.425)
0.753***
(0.085)
1.072***
(0.396)
0.742***
(0.085)
1.070***
(0.397)
0.736***
(0.085)
1.073***
0.226**
(0.109)
0.718***
(0.096)
0.450***
(0.078)
0.291***
(0.110)
0.654***
(0.096)
0.463***
(0.077)
0.251**
(0.107)
0.689***
(0.094)
0.457***
(0.075)
0.207**
(0.093)
0.511***
(0.079)
0.306***
(0.067)
0.206**
(0.093)
0.498***
(0.080)
0.305***
(0.067)
(0.397)
0.193**
(0.094)
0.475***
(0.081)
0.311***
(0.067)
0.000***
(0.000)
0.000***
(0.000)
-0.000***
(0.000)
0.000***
(0.000)
0.000***
(0.000)
-0.000***
(0.000)
0.000***
(0.000)
0.000***
(0.000)
-0.000***
(0.000)
0.000***
(0.000)
0.000***
(0.000)
-0.000***
(0.000)
0.000***
(0.000)
0.000***
(0.000)
-0.000***
(0.000)
0.000***
(0.000)
0.000***
(0.000)
-0.000***
(0.000)
0.742***
(0.113)
-0.218***
(0.073)
0.888***
(0.096)
0.731***
(0.115)
-0.176**
(0.073)
0.909***
(0.095)
0.707***
(0.113)
-0.270***
(0.072)
0.907***
(0.094)
0.277***
(0.096)
-0.285***
(0.069)
0.549***
(0.079)
0.279***
(0.096)
-0.295***
(0.068)
0.528***
(0.081)
0.293***
(0.097)
-0.229***
(0.070)
0.570***
(0.085)
1.002***
(0.087)
0.984***
(0.087)
0.943***
(0.086)
0.311***
(0.080)
0.309***
(0.080)
0.315***
(0.080)
-0.080
(0.073)
-0.048
(0.073)
-0.000*
(0.000)
-0.034
(0.072)
-0.000
(0.000)
0.435***
-0.171***
(0.065)
-0.000**
(0.000)
0.420***
-0.166**
(0.065)
-0.000**
(0.000)
0.421***
-0.157**
(0.065)
-0.000**
(0.000)
0.432***
(0.051)
(0.050)
0.403***
(0.049)
0.402***
(0.050)
0.401***
(0.025)
(0.025)
0.012**
(0.005)
-8.238***
(0.340)
153894
-8.261***
(0.337)
153244
(0.025)
0.011**
(0.005)
-0.011***
(0.004)
-8.265***
(0.341)
153244
Total Trade
Supplier’s Nuclear
Resources
Importer’s Nuclear
Resources
Energy Demand
Oil Price
Constant
Observations
-4.252***
(0.105)
156166
-4.261***
(0.104)
153894
-7.017***
(0.336)
153894
5
Notes: * significant at 10%; ** significant at 5%; *** significant at 1%. Robust standard errors in
parentheses. Results for years passing without signing of nuclear cooperation agreement and 3 cubic
splines are not reported in the interest of space.
Table II: Results without Safety-Related NCAs
(1)
Supplier’s
Strategic
Interests
Alliance
Militarized
Conflict
(2)
(3)
(4)
(5)
1.922***
(0.087)
-0.324
(0.392)
Shared Enemy
Superpower
Enemy
1.456***
(0.103)
1.464***
(0.080)
Joint Democracy
Economic
Incentives
Supplier’s GDP
Recipient’s GDP
Distance
Nonproliferation
Nuclear Weapons
NPT
NSG
Contagion
Effects
Regional NCAs
Constant
0.969***
(0.082)
(6)
(7)
1.476***
(0.097)
-0.588
1.036***
(0.097)
-0.839**
(0.383)
0.557***
(0.107)
1.124***
(0.395)
0.189*
(0.106)
0.699***
(0.082)
0.514***
(0.080)
(0.095)
0.347***
(0.085)
0.000***
(0.000)
0.000***
(0.000)
-0.000***
(0.000)
0.760***
(0.111)
-0.473***
(0.076)
0.632***
(0.100)
1.005***
(0.089)
-4.625***
(0.120)
156166
-3.922***
-3.387***
-3.580***
-3.755***
-3.807***
-4.418***
(0.097)
(0.096)
(0.090)
(0.091)
(0.099)
(0.100)
Observations
161492
161492
161492
161492
161492
161492
Notes: * significant at 10%; ** significant at 5%; *** significant at 1%. Robust standard errors in parentheses.
Results for years passing without signing of nuclear cooperation agreement and 3 cubic splines are not reported in
the interest of space.
6
Table III: Results for Only Major Suppliers
(1)
Supplier’s
Strategic
Interests
Alliance
Militarized
Conflict
(2)
(3)
(4)
(5)
1.494***
(0.116)
-0.806
(0.565)
Shared Enemy
Superpower
Enemy
1.219***
(0.121)
1.247***
(0.105)
Joint Democracy
Economic
Incentives
Supplier’s GDP
Recipient’s GDP
Distance
Nonproliferation
Nuclear Weapons
NPT
NSG
Contagion
Effects
Regional NCAs
Constant
0.813***
(0.110)
(6)
(7)
1.140***
(0.116)
-1.154**
0.700***
(0.122)
-1.419**
(0.552)
0.541***
(0.124)
0.902***
(0.596)
0.246**
(0.125)
0.674***
(0.118)
0.378***
(0.098)
(0.123)
0.168*
(0.102)
0.000***
(0.000)
0.000***
(0.000)
-0.000
(0.000)
0.562***
(0.140)
-0.314***
(0.094)
0.978***
(0.139)
0.947***
(0.110)
-3.586***
(0.119)
47512
-2.580***
-1.997***
-2.241***
-2.321***
-2.433***
-2.987***
(0.121)
(0.110)
(0.097)
(0.101)
(0.114)
(0.110)
Observations
49243
49243
49243
49243
49243
49243
Notes: * significant at 10%; ** significant at 5%; *** significant at 1%. Robust standard errors in parentheses.
Results for years passing without signing of nuclear cooperation agreement and 3 cubic splines are not reported in
the interest of space.
7
References
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Jo, Dong-Joon, and Erik Gartzke. 2007. Determinants of nuclear weapons proliferation.
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