The data also suggest that theories that explain the use of contracts by historical conventions leave many themes unexplained. Although some scientists, for example, have argued that dependence on pathways explains why treaties are particularly common in human rights and are lacking in trade, Table 2 shows that neither subject is a particularly striking outlier. While in the field of human rights treaties are somewhat widespread (17 per cent of all agreements), the choice of this instrument remains the exception and not the norm. Similarly, the application of contracts in sectors such as trade, trade and finance is close to the 5% average, raising the question of whether the scarcity of the instrument in these areas can best be explained by historical events or whether it reflects another aversion to the treaty, which also concerns other areas. In summary, it is difficult to explain the diversity of contract prevalence in the different disciplines of conventional theories. Finally, the data set does not contain any information on which party is the first responsible for the end of the agreement. All of the above theories focus on the reliability of the United States as negotiating partners. Agreements that are denounced for reasons that have nothing to do with the U.S. commitment should therefore not be included in the analysis. Footnote 85 At the same time, the identity of the party responsible for terminating the contract is not respected, unless the researcher analyzes each termination individually. Even then, identifying the responsible party is often a subjective assessment. However, the inability to monitor accountability for the breakdown of agreements is unlikely to result in significant distortions in the estimates derived from the data.

Bias is introduced only if an unsured variable is related to both interest variables and outcome variables. This means that bias is only introduced if the probability for the other party to violate the agreement is different between the contracts and the executive agreements of Congress. Footnote 86 As noted above, only the United States