Using a novel methodology, we offer new evidence that a threshold relationship exists for Okun's law (the well-known output–unemployment co-movement). We use a logistic smooth transition regression (LSTR) model where threshold endogeneity is addressed using copula transformations of the threshold variable. We also suggest a test of the linearity hypothesis against the LSTR model. In line with Okun's insight (and that of the subsequent literature) that the trade-off can be affected by different margins, we consider several potential threshold variables. We find mainly a combination of structural and policy-related variables accounts for changes in the Okun's law trade-off for the United States in recent decades. This conclusion is bolstered by combing these threshold candidates into a single factor. Accordingly, we find that the unemployment gap is increasingly associated with a smaller output gap. Notably, while the Great Recession accelerated that rise, the bulk of the change occurred beforehand.

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探索奥肯定律的不对称性：一种内生阈值逻辑平滑过渡回归方法*

我们使用一种新颖的方法提供了新的证据，证明奥肯定律（众所周知的产出-失业联动）存在阈值关系。我们使用逻辑平滑过渡回归 (LSTR) 模型，其中使用阈值变量的 copula 变换解决阈值内生性问题。我们还建议针对 LSTR 模型检验线性假设。根据 Okun 的见解（以及后续文献的见解），权衡可能会受到不同利润率的影响，我们考虑了几个潜在的阈值变量。我们发现，近几十年来美国奥肯定律权衡的变化主要是结构变量和政策相关变量的组合。通过将这些候选阈值组合成一个因素来支持这一结论。因此，我们发现，失业差距越来越多地与较小的产出差距相关联。值得注意的是，虽然大衰退加速了这种上升，但大部分变化都是事先发生的。