The Effects of Treaty Legality and Domestic Institutional Hurdles on Environmental Treaty

Online Appendix

The effects of treaty legality and domestic institutional hurdles on environmental treaty ratification.

Table A.1: Model with GDP per capita squared

(1) / (2)
Logit regression / Logit regression
Hard treaty / -0.27*** / -0.27***
(0.035) / (0.035)
Legislative approval / 0.16
(0.122)
Legislative approval: majority / 0.18
(0.121)
Legislative approval: supermajority / -0.39**
(0.184)
ln trade openness / 0.04 / 0.04
(0.079) / (0.079)
IGO membership / -0.00 / -0.00
(0.003) / (0.003)
Polity / 0.02*** / 0.02***
(0.006) / (0.006)
ln GDP pc / 0.25 / 0.16
(0.548) / (0.530)
ln GDP pc2 / -0.01 / -0.00
(0.033) / (0.032)
ln SO2 pc / 0.07** / 0.07**
(0.032) / (0.032)
Number of countries ratified / 0.02*** / 0.02***
(0.002) / (0.002)
Number of countries in same income group / -0.00 / -0.00
(0.003) / (0.003)
Number of countries in same region / 0.03*** / 0.03***
(0.002) / (0.002)
ln GDP / 0.12*** / 0.13***
(0.033) / (0.033)
Assistance / 0.30*** / 0.30***
(0.047) / (0.047)
Assistance developing countries / 0.55*** / 0.55***
(0.081) / (0.081)
Global public good / -0.55*** / -0.55***
(0.043) / (0.044)
Mixed global public good / -0.38*** / -0.38***
(0.054) / (0.054)
t / -0.32*** / -0.32***
(0.016) / (0.016)
t2 / 0.01*** / 0.01***
(0.001) / (0.001)
t3 / -0.00*** / -0.00***
(0.000) / (0.000)
Constant / -6.99*** / -6.95***
(2.451) / (2.392)
Log Likelihood / -26008.397 / -25984.018
Pseudo R2 / 0.19 / 0.19
Observations / 538,036 / 538,036
Robust standard errors in parentheses, clustered at country level
*** p<0.01, ** p<0.05, * p<0.10

Table A.2: Model with standard errors that cluster at the treaty-country (model 1 and 2) respectively at the treaty (model 3 and 4) level

(1) / (2) / (3) / (4)
Logit regression / Logit regression / Logit regression / Logit regression
Hard treaty / -0.27*** / -0.27*** / -0.27*** / -0.27***
(0.035) / (0.035) / (0.098) / (0.098)
Legislative approval / 0.17*** / 0.17***
(0.043) / (0.055)
Legislative approval: majority / 0.18*** / 0.18***
(0.043) / (0.054)
Legislative approval: supermajority / -0.39*** / -0.39***
(0.111) / (0.111)
ln trade openness / 0.04 / 0.04 / 0.04 / 0.04
(0.030) / (0.030) / (0.037) / (0.037)
IGO membership / -0.00 / -0.00* / -0.00 / -0.00
(0.001) / (0.001) / (0.003) / (0.003)
Polity / 0.02*** / 0.02*** / 0.02*** / 0.02***
(0.003) / (0.003) / (0.004) / (0.004)
ln GDP pc / 0.12*** / 0.13*** / 0.12*** / 0.13***
(0.026) / (0.026) / (0.044) / (0.044)
ln SO2 pc / 0.07*** / 0.07*** / 0.07*** / 0.07***
(0.015) / (0.015) / (0.020) / (0.020)
Number of countries ratified / 0.02*** / 0.02*** / 0.02*** / 0.02***
(0.001) / (0.001) / (0.003) / (0.003)
Number of countries in same income group / -0.00** / -0.00** / -0.00 / -0.00
(0.002) / (0.002) / (0.003) / (0.003)
Number of countries in same region / 0.03*** / 0.03*** / 0.03*** / 0.03***
(0.001) / (0.001) / (0.003) / (0.003)
ln GDP / 0.12*** / 0.13*** / 0.12*** / 0.13***
(0.013) / (0.013) / (0.020) / (0.021)
Assistance / 0.30*** / 0.30*** / 0.30** / 0.30**
(0.046) / (0.046) / (0.130) / (0.130)
Assistance developing countries / 0.55*** / 0.55*** / 0.55*** / 0.55***
(0.056) / (0.056) / (0.193) / (0.193)
Global public good / -0.55*** / -0.55*** / -0.55*** / -0.55***
(0.034) / (0.034) / (0.109) / (0.110)
Mixed global public good / -0.38*** / -0.38*** / -0.38 / -0.38
(0.063) / (0.063) / (0.277) / (0.277)
t / -0.32*** / -0.32*** / -0.32*** / -0.32***
(0.008) / (0.008) / (0.024) / (0.024)
t2 / 0.01*** / 0.01*** / 0.01*** / 0.01***
(0.001) / (0.001) / (0.001) / (0.001)
t3 / -0.00*** / -0.00*** / -0.00*** / -0.00***
(0.000) / (0.000) / (0.000) / (0.000)
Constant / -6.46*** / -6.84*** / -6.46*** / -6.84***
(0.454) / (0.457) / (0.594) / (0.605)
Log Likelihood / -26008.397 / -25984.018 / -26008.397 / -25984.018
Pseudo R2 / 0.19 / 0.19 / 0.19 / 0.19
Observations / 538,036 / 538,036 / 538,036 / 538,036
Robust standard errors in parentheses, *** p<0.01, ** p<0.05, * p<0.10

Table A.3: This table shows the results if we replace our original hard treaty measure with an additive index of hard treaty. The original measure takes on the value of 1 if two out of three dimensions (dispute settlement, monitoring/enforcement and quantitative targets) are present and is zero otherwise. In contrast, the additive hard law measure sums the three different components and thus ranges from zero to three.

(1) / (2)
Logit regression / Logit regression
Hard treaty: additive index / -0.17*** / -0.17***
(0.019) / (0.019)
Legislative approval / 0.17
(0.120)
Legislative approval: majority / 0.18
(0.119)
Legislative approval: supermajority / -0.39**
(0.184)
ln trade openness / 0.05 / 0.05
(0.078) / (0.077)
IGO membership / -0.00 / -0.00
(0.003) / (0.003)
Polity / 0.02*** / 0.02***
(0.006) / (0.006)
ln GDP pc / 0.12** / 0.13**
(0.057) / (0.057)
ln SO2 pc / 0.07** / 0.07**
(0.032) / (0.032)
Number of countries ratified / 0.02*** / 0.02***
(0.002) / (0.002)
Number of countries in same income group / -0.00 / -0.00
(0.003) / (0.003)
Number of countries in same region / 0.03*** / 0.03***
(0.002) / (0.002)
ln GDP / 0.12*** / 0.13***
(0.033) / (0.032)
Assistance / 0.32*** / 0.32***
(0.046) / (0.047)
Assistance developing countries / 0.55*** / 0.55***
(0.080) / (0.079)
Global public good / -0.52*** / -0.52***
(0.043) / (0.043)
Mixed global public good / -0.35*** / -0.35***
(0.054) / (0.054)
t / -0.32*** / -0.32***
(0.016) / (0.016)
t2 / 0.01*** / 0.01***
(0.001) / (0.001)
t3 / -0.00*** / -0.00***
(0.000) / (0.000)
Constant / -6.46*** / -6.84***
(1.040) / (1.050)
Log Likelihood / -25991.834 / -25967.681
Pseudo R2 / 0.19 / 0.19
Observations / 538,036 / 538,036
Robust standard errors in parentheses, clustered at country level
*** p<0.01, ** p<0.05, * p<0.10

Table A.4: In this table, we show the results if we replace one component, monitoring and enforcement of our hard treaty measure. Our original measure is based on the coding that requires both monitoring and enforcement to be present. In this revised measure only one of the two components (monitoring and enforcement) needs to be present.

(1) / (2)
Logit regression / Logit regression
Hard treaty: enf or mon / -0.33*** / -0.33***
(0.038) / (0.038)
Legislative approval / 0.17
(0.120)
Legislative approval: majority / 0.18
(0.119)
Legislative approval: supermajority / -0.39**
(0.183)
ln trade openness / 0.05 / 0.04
(0.078) / (0.077)
IGO membership / -0.00 / -0.00
(0.003) / (0.003)
Polity / 0.02*** / 0.02***
(0.006) / (0.006)
ln GDP pc / 0.12** / 0.13**
(0.057) / (0.057)
ln SO2 pc / 0.07** / 0.07**
(0.032) / (0.032)
Number of countries ratified / 0.02*** / 0.02***
(0.002) / (0.002)
Number of countries in same income group / -0.00 / -0.00
(0.003) / (0.003)
Number of countries in same region / 0.03*** / 0.03***
(0.002) / (0.002)
ln GDP / 0.12*** / 0.13***
(0.033) / (0.032)
Assistance / 0.27*** / 0.27***
(0.045) / (0.045)
Assistance developing countries / 0.54*** / 0.54***
(0.078) / (0.077)
Global public good / -0.51*** / -0.51***
(0.042) / (0.043)
Mixed global public good / -0.36*** / -0.36***
(0.053) / (0.053)
t / -0.32*** / -0.32***
(0.016) / (0.016)
t2 / 0.01*** / 0.01***
(0.001) / (0.001)
t3 / -0.00*** / -0.00***
(0.000) / (0.000)
Constant / -6.44*** / -6.82***
(1.039) / (1.048)
Log Likelihood / -25991.248 / -25966.962
Pseudo R2 / 0.19 / 0.19
Observations / 538,036 / 538,036
Robust standard errors in parentheses, clustered at country level
*** p<0.01, ** p<0.05, * p<0.10

Table A.5: Column 1 shows the results if we replace the hard treaty measure by a measure that only becomes one if all three characteristics (dispute settlement, monitoring/enforcement and quantitative targets) are present. Column 2 shows the results if only one component needs to be present for the variable to be coded as one.

(1) / (2)
Logit regression / Logit regression
Hard treaty: all=1 / -0.23***
(0.045)
Hard treaty: only one / -0.33***
(0.043)
Legislative approval / 0.17 / 0.17
(0.122) / (0.120)
ln trade openness / 0.04 / 0.05
(0.078) / (0.078)
IGO membership / -0.00 / -0.00
(0.003) / (0.003)
Polity / 0.02*** / 0.02***
(0.006) / (0.006)
ln GDP pc / 0.12** / 0.12**
(0.057) / (0.057)
ln SO2 pc / 0.07** / 0.07**
(0.032) / (0.031)
Number of countries ratified / 0.02*** / 0.02***
(0.002) / (0.002)
Number of countries in same income group / -0.00 / -0.00
(0.003) / (0.003)
Number of countries in same region / 0.03*** / 0.03***
(0.002) / (0.002)
ln GDP / 0.12*** / 0.12***
(0.033) / (0.032)
Assistance / 0.31*** / 0.26***
(0.045) / (0.045)
Assistance developing countries / 0.45*** / 0.46***
(0.075) / (0.076)
Global public good / -0.55*** / -0.48***
(0.043) / (0.042)
Mixed global public good / -0.47*** / -0.37***
(0.055) / (0.055)
t / -0.32*** / -0.32***
(0.016) / (0.016)
t2 / 0.01*** / 0.01***
(0.001) / (0.001)
t3 / -0.00*** / -0.00***
(0.000) / (0.000)
Constant / -6.54*** / -6.46***
(1.042) / (1.034)
Log Likelihood / -26034.338 / -26005.87
Pseudo R2 / 0.19 / 0.19
Observations / 538,036 / 538,036
Robust standard errors in parentheses, clustered at country level
*** p<0.01, ** p<0.05, * p<0.10

Table A.6: Model controlling for special incentives for certain countries such as lower emission targets.

(1) / (2)
Logit regression / Logit regression
Hard treaty / -0.28*** / -0.28***
(0.036) / (0.036)
Legislative approval / 0.17
(0.121)
Legislative approval: majority / 0.18
(0.120)
Legislative approval: supermajority / -0.39**
(0.184)
ln trade openness / 0.04 / 0.04
(0.079) / (0.078)
IGO membership / -0.00 / -0.00
(0.003) / (0.003)
Polity / 0.02*** / 0.02***
(0.006) / (0.006)
ln GDP pc / 0.12** / 0.13**
(0.058) / (0.057)
ln SO2 pc / 0.07** / 0.07**
(0.032) / (0.032)
Number of countries ratified / 0.02*** / 0.02***
(0.002) / (0.002)
Number of countries in same income group / -0.00 / -0.00
(0.003) / (0.003)
Number of countries in same region / 0.03*** / 0.03***
(0.002) / (0.002)
ln GDP / 0.12*** / 0.13***
(0.033) / (0.033)
Assistance / 0.30*** / 0.30***
(0.047) / (0.047)
Assistance developing countries / 0.54*** / 0.54***
(0.078) / (0.077)
Global public good / -0.55*** / -0.55***
(0.047) / (0.047)
Mixed global public good / -0.38*** / -0.38***
(0.053) / (0.053)
Special incentives / 0.03 / 0.04
(0.046) / (0.047)
t / -0.32*** / -0.32***
(0.016) / (0.016)
t2 / 0.01*** / 0.01***
(0.001) / (0.001)
t3 / -0.00*** / -0.00***
(0.000) / (0.000)
Constant / -6.46*** / -6.84***
(1.049) / (1.059)
Log Likelihood / -26008.04 / -25983.64
Pseudo R2 / 0.19 / 0.19
Observations / 538,036 / 538,036
Robust standard errors in parentheses, clustered at country level
*** p<0.01, ** p<0.05, * p<0.10

Table A.7: Is the influence of supermajority due to the US?

(1)
No US
Hard treaty / -0.27***
(0.035)
Legislative approval: majority / 0.18
(0.120)
Legislative approval: supermajority / -0.45*
(0.244)
ln trade openness / 0.04
(0.080)
IGO membership / -0.00
(0.003)
Polity / 0.02***
(0.006)
ln GDP pc / 0.13**
(0.057)
ln SO2 pc / 0.07**
(0.032)
Number of countries ratified / 0.02***
(0.002)
Number of countries in same income group / -0.00
(0.003)
Number of countries in same region / 0.03***
(0.002)
ln GDP / 0.13***
(0.033)
Assistance / 0.30***
(0.047)
Assistance developing countries / 0.56***
(0.082)
Global public good / -0.56***
(0.043)
Mixed global public good / -0.39***
(0.054)
t / -0.32***
(0.016)
t2 / 0.01***
(0.001)
t3 / -0.00***
(0.000)
Constant / -6.92***
(1.058)
Log Likelihood / -25712.482
Pseudo R2 / 0.19
Observations / 534,845
Robust standard errors in parentheses, clustered at country level; *** p<0.01, ** p<0.05, * p<0.10

Table A.8: Model with one diffusion variable at a time

(1) / (2) / (3)
Logit regression / Logit regression / Logit regression
Hard treaty / -0.29*** / -0.30*** / -0.33***
(0.032) / (0.032) / (0.034)
Legislative approval / 0.21* / 0.26** / 0.13
(0.121) / (0.131) / (0.121)
ln trade openness / -0.02 / 0.09 / 0.12
(0.080) / (0.074) / (0.074)
IGO membership / 0.00 / 0.00 / -0.00
(0.003) / (0.003) / (0.003)
Polity / 0.03*** / 0.03*** / 0.02***
(0.006) / (0.006) / (0.006)
ln GDP pc / 0.21*** / 0.01 / 0.02
(0.055) / (0.055) / (0.055)
ln SO2 pc / 0.07** / 0.07** / 0.07**
(0.032) / (0.033) / (0.031)
Number of countries ratified / 0.03***
(0.001)
Number of countries in same income group / 0.05***
(0.002)
Number of countries in same region / 0.05***
(0.002)
ln GDP / 0.08** / 0.09*** / 0.15***
(0.032) / (0.031) / (0.033)
Assistance / 0.28*** / 0.50*** / 0.53***
(0.048) / (0.051) / (0.044)
Assistance developing countries / 0.46*** / 0.91*** / 0.94***
(0.085) / (0.084) / (0.080)
Global public good / -0.56*** / -0.59*** / -0.62***
(0.040) / (0.037) / (0.042)
Mixed global public good / -0.42*** / -0.47*** / -0.46***
(0.050) / (0.053) / (0.056)
t / -0.30*** / -0.29*** / -0.29***
(0.015) / (0.018) / (0.016)
t2 / 0.01*** / 0.01*** / 0.01***
(0.001) / (0.001) / (0.001)
t3 / -0.00*** / -0.00*** / -0.00***
(0.000) / (0.000) / (0.000)
Constant / -6.08*** / -5.38*** / -6.42***
(1.057) / (1.047) / (1.011)
Log Likelihood / -26543.304 / -27198.933 / -26442.429
Pseudo R2 / 0.17 / 0.15 / 0.17
Observations / 538,036 / 538,036 / 538,036
Robust standard errors in parentheses, *** p<0.01, ** p<0.05, * p<0.10

Table A.9: Including Negotiating Parties

Our analysis has treated the design of a treaty as given thereby neglecting the possibility that it is usually the member countries themselves that decide in the first place whether a treaty should be ‘hard’ or ‘soft’. This would pose a problem for our analysis if, for example, potential member countries designed a treaty as ‘hard’ or ‘soft’ in order to influence its ratification chances. To show that the negotiation phase does not affect the results of our analysis, we collected data on whether a particular country participated in the negotiation phase of a specific treaty. The data were collected from official sources such as the treaty secretariats and/or treaty texts. In cases we were not able to find any information on the negotiating parties we considered the countries that signed a given treaty within its first month of existence to be part of the negotiating group. The idea behind this proxy is that countries that participated in the negotiations should be more likely to immediately sign the agreement to signal their accordance with the final document of the treaty.

The results in Table 6A reveal that controlling for country participation in the negotiation phase does not affect our main results. The coefficient of the negotiation variable suggests that taking part in the negotiations of a particular treaty significantly increases the chances that this country will also ratify this treaty.

(1) / (2)
logit regression / logit regression
Hard treaty / -0.35*** / -0.35***
(0.035) / (0.035)
Legislative approval / 0.09
(0.117)
Legislative approval: majority / 0.11
(0.116)
Legislative approval: supermajority / -0.42**
(0.171)
ln trade openness / 0.00 / -0.01
(0.075) / (0.074)
IGO membership / -0.01** / -0.01**
(0.003) / (0.003)
Polity / 0.02*** / 0.02***
(0.006) / (0.006)
ln GDP pc / 0.15** / 0.15***
(0.059) / (0.058)
ln SO2 pc / 0.06* / 0.06*
(0.031) / (0.031)
Number of countries ratified / 0.02*** / 0.02***
(0.002) / (0.002)
Number of countries in same income group / -0.01* / -0.01*
(0.004) / (0.004)
Number of countries in same region / 0.03*** / 0.03***
(0.002) / (0.002)
ln GDP / 0.11*** / 0.13***
(0.033) / (0.033)
Assistance / 0.39*** / 0.39***
(0.047) / (0.047)
Assistance developing countries / 0.51*** / 0.51***
(0.073) / (0.073)
Global public good / -0.59*** / -0.59***
(0.040) / (0.041)
Mixed global public good / -0.38*** / -0.38***
(0.059) / (0.059)
Negotiating Party / 1.66*** / 1.65***
(0.062) / (0.062)
t / -0.27*** / -0.27***
(0.014) / (0.015)
t2 / 0.01*** / 0.01***
(0.001) / (0.001)
t3 / -0.00*** / -0.00***
(0.000) / (0.000)
Constant / -6.53*** / -6.85***
(1.043) / (1.050)
Log Likelihood / -24890.123 / -24869.696
Pseudo R2 / 0.22 / 0.22
Observations / 538,036 / 538,036
Robust standard errors in parentheses, clustered at country level
*** p<0.01, ** p<0.05, * p<0.10

Table A.10: Using a conditional log-log model (column 1) and controlling for right-censoring by dropping all treaties that came into being after 19.

(1) / (2)
Conditional logit / Logit regression
Hard treaty / -0.10** / -0.23***
(0.038) / (0.039)
Legislative approval / 0.10 / 0.14
(0.101) / (0.122)
ln trade openness / 0.22*** / 0.05
(0.065) / (0.080)
IGO membership / 0.01*** / 0.00
(0.003) / (0.003)
Polity / 0.02*** / 0.02***
(0.005) / (0.006)
ln GDP pc / 0.08* / 0.08
(0.047) / (0.061)
ln SO2 pc / 0.03 / 0.11***
(0.028) / (0.035)
Number of countries ratified / 0.01*** / 0.02***
(0.002) / (0.003)
Number of countries in same income group / -0.00 / 0.00
(0.003) / (0.004)
Number of countries in same region / 0.02*** / 0.03***
(0.002) / (0.003)
ln GDP / 0.13*** / 0.15***
(0.028) / (0.033)
Assistance / 1.04*** / 0.35***
(0.057) / (0.047)
Assistance developing countries / 1.79*** / 0.63***
(0.080) / (0.079)
Global public good / -0.25*** / -0.35***
(0.043) / (0.043)
Mixed global public good / -0.11* / -0.05
(0.059) / (0.059)
t / -0.35***
(0.019)
t2 / 0.01***
(0.001)
t3 / -0.00***
(0.000)
Constant / -6.65***
(1.101)
Log Likelihood / -27407.411 / -20938.576
Pseudo R2 / 0.19
Observations / 538,036 / 436,573
Robust standard errors in parentheses, *** p<0.01, ** p<0.05, * p<0.10

Table A.11: The table below shows the results if we only use the 22 main environmental treaties as defined by Roberts et al. (2004). The list of these treaties can be found in Table A.12 below.

(1) / (2)
Logit regression / Logit regression
Hard treaty / -0.35*** / -0.35***
(0.094) / (0.094)
Legislative approval / -0.00
(0.105)
Legislative approval: majority / 0.02
(0.103)
Legislative approval: supermajority / -0.62*
(0.342)
ln trade openness / 0.19* / 0.19*
(0.100) / (0.099)
IGO membership / 0.02*** / 0.02***
(0.003) / (0.003)
Polity / 0.03*** / 0.02***
(0.007) / (0.006)
ln GDP pc / -0.07 / -0.06
(0.063) / (0.063)
ln SO2 pc / 0.01 / 0.00
(0.038) / (0.038)
Number of countries ratified / 0.01*** / 0.01***
(0.003) / (0.003)
Number of countries in same income group / -0.00 / -0.00
(0.005) / (0.005)
Number of countries in same region / 0.02*** / 0.02***
(0.003) / (0.003)
ln GDP / 0.10*** / 0.11***
(0.037) / (0.036)
Assistance / 0.13* / 0.12
(0.080) / (0.078)
Assistance developing countries / 0.83*** / 0.82***
(0.135) / (0.134)
Global public good / -0.66*** / -0.66***
(0.078) / (0.078)
Mixed global public good / 0.49*** / 0.48***
(0.153) / (0.152)
t / -0.23*** / -0.23***
(0.025) / (0.025)
t2 / 0.01*** / 0.01***
(0.002) / (0.002)
t3 / -0.00*** / -0.00***
(0.000) / (0.000)
Constant / -5.71*** / -6.16***
(1.239) / (1.209)
Log Likelihood / -5768.7034 / -5761.0027
Pseudo R2 / 0.19 / 0.19
Observations / 47,333 / 47,333
Robust standard errors in parentheses, clustered at country level
*** p<0.01, ** p<0.05, * p<0.10

A.12: List of treaties used in Roberts et al. (2014)

Treatyname
International Convention On Civil Liability For Oil Pollution Damage
Convention On The Prevention Of Marine Pollution From Land-Based Sources
International Convention for the Regulation of Whaling
International Convention for the Prevention of Pollution of the Sea by Oil 1962 and 1969
Convention on Fishing and Conservation of the Living Resources of the High Seas
Convention on the High Seas
Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter
Convention on International Trade in Endangered Species of Wild Fauna and Flora
Convention on the Conservation of Migratory Species of Wild Animals
Convention on Long-Range Transboundary Air Pollution
Convention concerning the Protection of the World Cultural and Natural Heritage
Convention on Wetlands of International Importance especially as Waterfowl Habitat
Convention for the Protection of the Mediterranean Sea against Pollution
United Nations Convention on the Law of the Sea
Convention for the Protection of the Ozone Layer
Protocol on Substances that Deplete the Ozone Layer
Convention on Environmental Impact Assessment in a Transboundary Context
International Convention on Oil Pollution Preparedness Response and Co-operation
Convention on Transboundary Effects of Industrial Accidents
United Nations Framework Convention on Climate Change
Convention on Biological Diversity
International Convention to Combat Desertification in those Countries Experiencing Serious Drought and or Desertification

Table A.13: Instead of coding whether majority or supermajority is required, one could have also coded whether the lower house, the upper house or both houses are required for treaty ratification.

(1) / (2)
Logit regression / Logit regression
Hard treaty / -0.27*** / -0.27***
(0.035) / (0.035)
Legislative approval: lower house / 0.22*
(0.112)
Legislative approval: upper house / -0.01
(0.093)
Legislative approval: both houses / 0.09
(0.089)
ln trade openness / 0.04 / 0.04
(0.079) / (0.079)
IGO membership / -0.00 / -0.00
(0.003) / (0.003)
Polity / 0.02*** / 0.02***
(0.006) / (0.006)
ln GDP pc / 0.13** / 0.11**
(0.057) / (0.055)
ln SO2 pc / 0.07** / 0.08**
(0.032) / (0.032)
Number of countries ratified / 0.02*** / 0.02***
(0.002) / (0.002)
Number of countries in same income group / -0.00 / -0.00
(0.003) / (0.003)
Number of countries in same region / 0.03*** / 0.03***
(0.002) / (0.002)
ln GDP / 0.13*** / 0.12***
(0.032) / (0.032)
Assistance / 0.31*** / 0.30***
(0.047) / (0.047)
Assistance developing countries / 0.55*** / 0.55***
(0.082) / (0.082)
Global public good / -0.55*** / -0.55***
(0.043) / (0.044)
Mixed global public good / -0.38*** / -0.38***
(0.054) / (0.054)
t / -0.32*** / -0.32***
(0.016) / (0.016)
t2 / 0.01*** / 0.01***
(0.001) / (0.001)
t3 / -0.00*** / -0.00***
(0.000) / (0.000)
Constant / -6.68*** / -6.28***
(1.036) / (1.051)
Log Likelihood / -5768.7034 / -5761.0027
Pseudo R2 / 0.19 / 0.19
Observations / 538,036 / 538,036
Robust standard errors in parentheses, clustered at country level
*** p<0.01, ** p<0.05, * p<0.10

Table A.14: The results below are based on an index that takes on the value of one if majority voting is required in any of the two houses, two if supermajority is required in any of the two houses, and zero if no ratification is required.

(1)
Logit regression
Hard treaty / -0.27***
(0.035)
Legislative approval: index / 0.04
(0.099)
ln trade openness / 0.04
(0.080)
IGO membership / -0.00
(0.003)
Polity / 0.02***
(0.006)
ln GDP pc / 0.11*
(0.056)
ln SO2 pc / 0.07**
(0.032)
Number of countries ratified / 0.02***
(0.002)
Number of countries in same income group / -0.00
(0.003)
Number of countries in same region / 0.03***
(0.002)
ln GDP / 0.12***
(0.032)
Assistance / 0.30***
(0.047)
Assistance developing countries / 0.55***
(0.081)
Global public good / -0.55***
(0.043)
Mixed global public good / -0.38***
(0.054)
t / -0.32***
(0.016)
t2 / 0.01***
(0.001)
t3 / -0.00***
(0.000)
Constant / -6.32***
(1.050)
Log Likelihood / -26017.91
Pseudo R2 / 0.19
Observations / 538,036
Robust standard errors in parentheses, clustered at country level; *** p<0.01, ** p<0.05, * p<0.10

Table A.15: This table shows the percentage change of the odds of observing a positive outcome (i.e. treaty ratification).

Percentage change in the odds
Hard treaty / -24.0
Legislative approval: index / 18.0
ln trade openness / 4.3
IGO membership / -0.1
Polity / 2.3
ln GDP pc / 13
ln SO2 pc / 7.6
Number of countries ratified / 2.0
Number of countries in same income group / -0.4
Number of countries in same region / 3.4
ln GDP / 12.8
Assistance / 35.6
Assistance developing countries / 73.4
Global public good / -42.3
Mixed global public good / -31.7

A.16: Excluding countries in transition.

(1) / (2) / (3)
without transition countries / without legislative approval / without transition countries
Hard law / -0.29*** / -0.27*** / -0.29***
(0.038) / (0.035) / (0.038)
Legislative approval / 0.15
(0.123)
Legislative approval: majority / 0.07
(0.083)
Legislative approval: supermajority / -0.00
(0.003)
ln trade openness / 0.07 / 0.04 / 0.02***
(0.083) / (0.079) / (0.006)
IGO membership / -0.00 / -0.00 / 0.13**
(0.003) / (0.003) / (0.058)
Polity / 0.03*** / 0.02*** / 0.05
(0.006) / (0.006) / (0.033)
ln GDP pc / 0.13** / 0.10* / 0.02***
(0.059) / (0.056) / (0.002)
ln SO2 pc / 0.05 / 0.07** / -0.01**
(0.033) / (0.032) / (0.003)
Number of countries ratified / 0.02*** / 0.02*** / 0.03***
(0.002) / (0.002) / (0.003)
Number of countries in same income group / -0.01** / -0.00 / 0.15***
(0.003) / (0.003) / (0.036)
Number of countries in same region / 0.03*** / 0.03*** / 0.31***
(0.002) / (0.002) / (0.051)
ln GDP / 0.13*** / 0.13*** / 0.60***
(0.036) / (0.032) / (0.088)
Assistance / 0.31*** / 0.30*** / -0.57***
(0.051) / (0.047) / (0.048)
Assistance developing countries / 0.60*** / 0.55*** / -0.41***
(0.089) / (0.081) / (0.058)
Global public good / -0.58*** / -0.55*** / -0.32***
(0.047) / (0.043) / (0.017)
Mixed global public good / -0.41*** / -0.38*** / 0.01***
(0.058) / (0.054) / (0.001)
t / -0.32*** / -0.32*** / -0.00***
(0.017) / (0.016) / (0.000)
t2 / 0.01*** / 0.01*** / 0.07
(0.001) / (0.001) / (0.083)
t3 / -0.00*** / -0.00*** / -0.00
(0.000) / (0.000) / (0.003)
Constant / -7.14*** / -6.31*** / -7.55***
(1.100) / (1.050) / (1.118)
Log Likelihood / -23081.855 / -26018.613 / -23058.948
Pseudo R2 / 0.19 / 0.19 / 0.19
Observations / 494,723 / 538,036 / 494,723
Robust standard errors in parentheses; *** p<0.01, ** p<0.05, * p<0.1

A.17: Summary Statistics Continuous Variables

Mean / Std. Dev. / Min / Max / Observations
ln trade intensity / overall / 4.03 / 0.67 / 0.69 / 6.03 / N = 538,036
between / 0.61 / n = 34,192
within / 0.28 / T-bar = 15.74
IGO membership / overall / 52 / 20.00 / 1 / 134 / N = 538,036
between / 19.76 / n = 34,192
within / 10.06 / T-bar = 15.74
Polity / overall / 0.52 / 7.48 / -10 / 10 / N = 538,036
between / 6.78 / n = 34,192
within / 3.55 / T-bar = 15.74
ln GDP p.c. / overall / 8.18 / 1.06 / 5.64 / 10.69 / N = 538,036
between / 1.06 / n = 34,192
within / .22 / T-bar = 15.74
ln SO2 p.c. / overall / -12.07 / 1.47 / -19.19 / -6.04 / N = 538,036
between / 1.38 / n = 34,192
within / 0.57 / T-bar = 15.74
# of other countries that ratified / overall / 15.82 / 20.57 / 0 / 180 / N = 538,036
between / 19.62 / n = 34,192
within / 10.06 / T-bar = 15.74
% of same income group that ratified / overall / 7.96 / 13.04 / 0 / 100 / N = 538,036
between / 10.43 / n = 34,192
within / 6.63 / T-bar = 15.74
% of countries in region that ratified / overall / 6.15 / 13.39 / 0 / 100 / N = 538,036
between / 11.25 / n = 34,192
within / 6.24 / T-bar = 15.74
ln GDP / overall / 23.99 / 1.80 / 19.44 / 29.85 / N = 538,036
between / 1.79 / n = 34,192
within / 0.33 / T-bar = 15.74
t / overall / 15.85 / 12.69 / 0 / 50 / N = 538,036
between / 10.52 / n = 34,192
within / 8.35 / T-bar = 15.74

A.18: Frequencies Dummy Variables, Percentages in Parenthesis:

0 / 1
Ratification / 532,262
(98.93) / 5,774
(1.07)
Hard law / 304,035
(56.51) / 234,001
(43.49)
Legislative approval / 110,535
(20.54) / 427,501
(79.46)
Legislative approval: majority / 129,662
(24.10) / 408,374
(75.90)
Legislative approval: supermajority / 518,909
(96.45) / 19,127
(3.55)
Global public good / 199,319
(37.05) / 338,71
(62.95)
Mixed global public good / 498,314
(92.62) / 39,722
(7.38)
Assistance all countries / 494,980
(92.00) / 43,056
(8.00)
Assistance developing countries / 514,847
(95.69) / 23,189
(4.31)

Table A.19: Including treaty issue areas

(1) / (2)
Logit regression / Logit regression
Hard law / -0.25*** / -0.25***
(0.036) / (0.037)
Legislative approval / 0.16
(0.120)
Legislative approval: majority / 0.18
(0.118)
Legislative approval: supermajority / -0.40**
(0.181)
ln trade openness / 0.05 / 0.05
(0.077) / (0.077)
IGO membership / -0.00 / -0.00
(0.003) / (0.003)
Polity / 0.02*** / 0.02***
(0.006) / (0.006)
ln GDP pc / 0.13** / 0.13**
(0.057) / (0.056)
ln SO2 pc / 0.07** / 0.07**
(0.031) / (0.032)
Number of countries ratified / 0.02*** / 0.02***
(0.002) / (0.002)
Number of countries in same income group / -0.00 / -0.00
(0.003) / (0.003)
Number of countries in same region / 0.03*** / 0.03***
(0.002) / (0.002)
ln GDP / 0.12*** / 0.13***
(0.032) / (0.032)
Assistance / 0.26*** / 0.26***
(0.051) / (0.051)
Assistance developing countries / 0.62*** / 0.62***
(0.078) / (0.077)
Global public good / -0.44*** / -0.43***
(0.042) / (0.042)
Mixed global public good / -0.26*** / -0.26***
(0.050) / (0.051)
Pollution treaty / -0.22*** / -0.22***
(0.039) / (0.039)
Nuclear treaty / 0.01 / 0.01
(0.053) / (0.053)
Species treaty / -0.35*** / -0.35***
(0.046) / (0.046)
Habitat treaty / -0.17*** / -0.17***
(0.043) / (0.044)
t / -0.32*** / -0.32***
(0.016) / (0.016)
t2 / 0.01*** / 0.01***
(0.001) / (0.001)
t3 / -0.00*** / -0.00***
(0.000) / (0.000)
Constant / -6.48*** / -6.86***
(1.031) / (1.040)
Log Likelihood / -25938.701 / -25914.334
Pseudo R2 / 0.19 / 0.19
Observations / 583,237 / 583,237
Robust standard errors in parentheses, clustered at country level
*** p<0.01, ** p<0.05, * p<0.10

Table A.20: The table below shows the results if we rely on the medium size sample from Bernauer et al. (2010). A list of these treaties can be found in the corresponding online Appendix.

(1) / (2)
Logit regression / Logit regression
Hard treaty / -0.25*** / -0.25***
(0.046) / (0.047)
Legislative approval / 0.06
(0.107)
Legislative approval: majority / 0.08
(0.106)
Legislative approval: supermajority / -0.62***
(0.177)
ln trade openness / 0.06 / 0.06
(0.083) / (0.082)
IGO membership / 0.00 / 0.00
(0.003) / (0.003)
Polity / 0.02*** / 0.02***
(0.006) / (0.006)
ln GDP pc / 0.12** / 0.13**
(0.055) / (0.053)
ln SO2 pc / 0.05* / 0.05
(0.030) / (0.030)
Number of countries ratified / 0.02*** / 0.02***
(0.002) / (0.002)
Number of countries in same income group / -0.00 / -0.00
(0.003) / (0.003)
Number of countries in same region / 0.02*** / 0.02***
(0.002) / (0.002)
ln GDP / 0.13*** / 0.15***
(0.033) / (0.032)
Assistance / 0.34*** / 0.34***
(0.049) / (0.049)
Assistance developing countries / 0.50*** / 0.50***
(0.098) / (0.097)
Global public good / -0.31*** / -0.31***
(0.046) / (0.046)
Mixed global public good / 0.32*** / 0.31***
(0.109) / (0.109)
t / -0.27*** / -0.27***
(0.016) / (0.016)
t2 / 0.01*** / 0.01***
(0.001) / (0.001)
t3 / -0.00*** / -0.00***
(0.000) / (0.000)
Constant / -7.08*** / -7.54***
(1.038) / (1.031)
Log Likelihood / -17071.993 / -17097.357
Pseudo R2 / 0.18 / 0.18
Observations / 234,901 / 234,901
Robust standard errors in parentheses, clustered at country level
*** p<0.01, ** p<0.05, * p<0.10

References

Bernauer, T, Kalbhenn, A., Koubi, V., & Spilker, G. (2010). A comparison of international

and domestic sources of global governance dynamics. British Journal of Political Science, 40(3), 509-538.

Roberts, T. J., Park, B. C., & Vasquez, A. A. (2004). Who ratifies environmental treaties and

why? Institutionalism, structuralism and participation by 192 nations in 22 treaties. Global Environmental Politics, 4(3), 22-64.