The analysis sorts the agreements according to their lifespan and assumes that x-quantil is an exclusive executive agreement, x ∈ [0, 0.1]. For example, x -0.03 assumes that the 3% of the least durable agreements are one-off executive agreements. It then omits these agreements from the analysis, executes the preferred model (5) and counts the estimated coefficient on the contractual indicator and its standard defects. Keep in mind that the assumption that the least durable agreements are exclusive executive agreements is extremely restrictive. In fact, it is much more likely that some unique executive agreements will survive the agreements between Congress and the executive branch. This approach can therefore be expected to distort the sustainability of congressional executive agreements, making it more difficult to differentiate between tenure of contracts and executive agreements. While it can be shown that even in these restrictive assumptions, contracts are viable, this is particularly strong evidence of an increase in the lifespan of contracts. if I agree individually, t is a period, x refers to a series of covariates and h the danger rate, that is, the probability of an event occurring. A treaty therefore requires the approval of the U.S. Senate to enter into force, while an executive agreement does not. As explained in the text, as international agreements can be repealed at any time, survival periods are of an ongoing nature. However, since survival periods are measured only once a year when the TIF is published, the data can be described as continuous data grouped by year.
For truly continuous data in which an event can occur at any time, the Cox Proportion Hazard ModelFootnote 117 has emerged as a preferred choice by researchers, notes 118, as it is a semi-parametric model based on a few hypotheses. The popularity of this model is due to the fact that it can be estimated without making parametric assumptions about the base risk rate. For example, the researcher is not obliged to consider that survival decreases over time, exponentially or in other predefined ways at constant speed. However, the Cox model assumes that the data do not contain links, which means that no observations have exactly the same survival time. This is because links cannot occur when survival times are measured on a truly continuous scale. Researchers have developed several techniques that make the Cox model mobile even in the presence of links. The most accurate approach is the „precise method“ developed by veal and Prentice meat. Footnote 119 Intuitively, when two subjects survive exactly at i and k n periods, the exact method considers the alternative that I survived longer than k and the alternative that has survived longer than i, and opts for the jeniser which is more likely. Footnote 120 In data sets with many themes, periods and links, the exact method is not feasible because it is very intense mathematically.
The footnote 121 of the „Efron method“ brings us closer to the exact method, which does not suffer from comparable resource restrictions, but is a little less precise. While some doctrinal criticism persists about the widespread application of the congressional executive agreement in place of the treaty, footnote 34 is now the prevailing view that treaties and executive agreements in Congress legally replace the vast majority of agreements under national law. Footnote 35 This view is also reflected in Restatement (Third) of the Foreign Relations Law of the United States. Footnote 36 There, the American Law Institute notes: 82 Hathaway, supra note 1, at 1259 („[S]eparating executive agreements that are congressionally authorized from those who are not required akribisch search for authorizing legislation.